Add developer documentation for the Federation Sender and add a documentation mechanism using Sphinx. (#15265)

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Bump dtolnay/rust-toolchain from e12eda571dc9a5ee5d58eecf4738ec291c66f295 to fc3253060d0c959bea12a59f10f8391454a0b02d (#15304)

* Bump dtolnay/rust-toolchain

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from e12eda571dc9a5ee5d58eecf4738ec291c66f295 to fc3253060d0c959bea12a59f10f8391454a0b02d.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](https://github.com/dtolnay/rust-toolchain/compare/e12eda571dc9a5ee5d58eecf4738ec291c66f295...fc3253060d0c959bea12a59f10f8391454a0b02d

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* Allow running twisted trunk against other branches

I would like to do this so we can try Synapse's typechecking against a
specific branch that the project solicited tests for, see
https://mail.python.org/archives/list/twisted@python.org/message/GGO5JHA5S475AK6JZ3GCC3GIHGKQYM6Y/

* Changelog

As we use some nightly only options, e.g. to group and sort imports
consistently.

* Bump matrix-org/backend-meta from 1 to 2

Bumps [matrix-org/backend-meta](https://github.com/matrix-org/backend-meta) from 1 to 2.
- [Release notes](https://github.com/matrix-org/backend-meta/releases)
- [Commits](https://github.com/matrix-org/backend-meta/compare/v1...v2

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* Bump actions/checkout from 2 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2...v3

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* Bump docker/login-action from 1 to 2

Bumps [docker/login-action](https://github.com/docker/login-action) from 1 to 2.
- [Release notes](https://github.com/docker/login-action/releases)
- [Commits](https://github.com/docker/login-action/compare/v1...v2

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* Bump dawidd6/action-download-artifact from 2.25.0 to 2.26.0

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 2.25.0 to 2.26.0.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](https://github.com/dawidd6/action-download-artifact/compare/b59d8c6a6c5c6c6437954f470d963c0b20ea7415...5e780fc7bbd0cac69fc73271ed86edf5dcb72d67

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* Bump dawidd6/action-download-artifact from 2.24.3 to 2.25.0

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 2.24.3 to 2.25.0.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](https://github.com/dawidd6/action-download-artifact/compare/bd10f381a96414ce2b13a11bfa89902ba7cea07f...b59d8c6a6c5c6c6437954f470d963c0b20ea7415

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Bump dtolnay/rust-toolchain from 25dc93b901a87e864900a8aec6c12e9aa794c0c3 to e12eda571dc9a5ee5d58eecf4738ec291c66f295 (#15101)

* Bump dtolnay/rust-toolchain

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 25dc93b901a87e864900a8aec6c12e9aa794c0c3 to e12eda571dc9a5ee5d58eecf4738ec291c66f295.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](https://github.com/dtolnay/rust-toolchain/compare/25dc93b901a87e864900a8aec6c12e9aa794c0c3...e12eda571dc9a5ee5d58eecf4738ec291c66f295

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Bump dtolnay/rust-toolchain from 9cd00a88a73addc8617065438eff914dd08d0955 to 25dc93b901a87e864900a8aec6c12e9aa794c0c3 (#15060)

* Bump dtolnay/rust-toolchain

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 9cd00a88a73addc8617065438eff914dd08d0955 to 25dc93b901a87e864900a8aec6c12e9aa794c0c3.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](https://github.com/dtolnay/rust-toolchain/compare/9cd00a88a73addc8617065438eff914dd08d0955...25dc93b901a87e864900a8aec6c12e9aa794c0c3

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* Skip testing PyPy wheels

One of the test builds on #15015 failed to install a pp38-* wheel
because it didn't have access to the openssl headers to build
`cryptography` from source. We don't run CI against PyPy so I'm going to
be a meanie and skip testing the wheels. (And I've no idea why 3.8 was
special in the first place, either.)

* Hack the name of the wheel so cibw can test it

I hate hate hate hate hate hate hate hate hate this

* Changelog

* Apply suggestions from code review

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

---------

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Bump dtolnay/rust-toolchain from e645b0cf01249a964ec099494d38d2da0f0b349f to 9cd00a88a73addc8617065438eff914dd08d0955 (#14968)

Signed-off-by: Jason Little <realtyem@gmail.com>

* Bump docker/build-push-action from 3 to 4

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 3 to 4.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v3...v4

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* Bump peaceiris/actions-gh-pages from 3.9.1 to 3.9.2

Bumps [peaceiris/actions-gh-pages](https://github.com/peaceiris/actions-gh-pages) from 3.9.1 to 3.9.2.
- [Release notes](https://github.com/peaceiris/actions-gh-pages/releases)
- [Changelog](https://github.com/peaceiris/actions-gh-pages/blob/main/CHANGELOG.md)
- [Commits](https://github.com/peaceiris/actions-gh-pages/compare/64b46b4226a4a12da2239ba3ea5aa73e3163c75b...bd8c6b06eba6b3d25d72b7a1767993c0aeee42e7

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* Upgrade to new lockfile format

Now requires poetry >= 1.2.2 to read and poetry >= 1.3.0 to write.

Cheat sheet:

```
poetry --version
poetry show > scratch/before
pipx upgrade poetry
poetry --version
poetry show > scratch/after
diff scratch{before,after} && echo "no change!"
```

* Use Poetry 1.3.2 when reading or writing lockfile

* Remove unneeded(?) poetry dep for cibuildwheel

* Update docs

* Remove redundant call to setup-python

* Remove outdated comments related to Poetry 1.x

* Remove outdated docs line

was fixed in #13082

* Minor improvements to poetry cheat sheet

* Invoke setup-python-poetry with explicit version

Not sure about this. It's hardcoding versions everywhere.

* Changelog

* Check the lockfile is version 2.0

Might one day incorporate other checks like #14742

* Typo fixes, thanks Sean

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

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* Bump peaceiris/actions-gh-pages from 3.9.0 to 3.9.1

Bumps [peaceiris/actions-gh-pages](https://github.com/peaceiris/actions-gh-pages) from 3.9.0 to 3.9.1.
- [Release notes](https://github.com/peaceiris/actions-gh-pages/releases)
- [Changelog](https://github.com/peaceiris/actions-gh-pages/blob/main/CHANGELOG.md)
- [Commits](https://github.com/peaceiris/actions-gh-pages/compare/de7ea6f8efb354206b205ef54722213d99067935...64b46b4226a4a12da2239ba3ea5aa73e3163c75b

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* Add htmltest to check links in the documentation

* Newsfile

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* Bump JasonEtco/create-an-issue from 2.8.2 to 2.9.1

Bumps [JasonEtco/create-an-issue](https://github.com/JasonEtco/create-an-issue) from 2.8.2 to 2.9.1.
- [Release notes](https://github.com/JasonEtco/create-an-issue/releases)
- [Commits](https://github.com/JasonEtco/create-an-issue/compare/3a8ba796516b57db8cb2ee6dfc65bc76cd39d56d...e27dddc79c92bc6e4562f268fffa5ed752639abd

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* Bump dawidd6/action-download-artifact from 2.24.2 to 2.24.3

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 2.24.2 to 2.24.3.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](https://github.com/dawidd6/action-download-artifact/compare/e6e25ac3a2b93187502a8be1ef9e9603afc34925...bd10f381a96414ce2b13a11bfa89902ba7cea07f

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ruff is a flake8-compatible Python linter written in Rust.
It supports the flake8 plugins that we use and is significantly
faster in testing.

* Bump JasonEtco/create-an-issue from 2.8.1 to 2.8.2

Bumps [JasonEtco/create-an-issue](https://github.com/JasonEtco/create-an-issue) from 2.8.1 to 2.8.2.
- [Release notes](https://github.com/JasonEtco/create-an-issue/releases)
- [Commits](https://github.com/JasonEtco/create-an-issue/compare/77399b6110ef82b94c1c9f9f615acf9e604f7f56...3a8ba796516b57db8cb2ee6dfc65bc76cd39d56d

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* Bump JasonEtco/create-an-issue from 2.5.0 to 2.8.1

Bumps [JasonEtco/create-an-issue](https://github.com/JasonEtco/create-an-issue) from 2.5.0 to 2.8.1.
- [Release notes](https://github.com/JasonEtco/create-an-issue/releases)
- [Commits](https://github.com/JasonEtco/create-an-issue/compare/5d9504915f79f9cc6d791934b8ef34f2353dd74d...77399b6110ef82b94c1c9f9f615acf9e604f7f56

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Co-authored-by: Michael Kaye <1917473+michaelkaye@users.noreply.github.com>

* GHA workflow to build complement images of key branches.

* Add changelog.d

* GHA workflow to build complement images of key branches.

* Add changelog.d

* Update complement.yml

Remove special casing for michaelk branch.

* Update complement.yml

Should run on master, develop not main, develop

* Rename file to be more obvious

* Merge did not go correctly.

* Setup 5am builds of develop, limit to one run at once.

* Fix crontab---run once at 5AM, not very minute between 5 and 6

* Fix cron syntax again?

* Tweak workflow name

* Allow manual debug runs

* Tweak indentation

Ctrl-Alt-L in PyCharm

Co-authored-by: David Robertson <david.m.robertson1@gmail.com>
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* Run Rust CI when Cargo.lock changes too

* Changelog

Bump dtolnay/rust-toolchain from 55c7845fad90d0ae8b2e83715cb900e5e861e8cb to e645b0cf01249a964ec099494d38d2da0f0b349f (#14557)

* Bump dtolnay/rust-toolchain

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 55c7845fad90d0ae8b2e83715cb900e5e861e8cb to e645b0cf01249a964ec099494d38d2da0f0b349f.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](https://github.com/dtolnay/rust-toolchain/compare/55c7845fad90d0ae8b2e83715cb900e5e861e8cb...e645b0cf01249a964ec099494d38d2da0f0b349f

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This is to help downstream packagers.

* Bump actions/upload-artifact from 2 to 3

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2 to 3.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v2...v3

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