Merge branch 'develop' into jaywink/admin-forward-extremities

changelog.d/9121.bugfix

changelog.d/9209.feature

docs/admin_api/user_admin_api.rst

stubs/txredisapi.pyi

synapse/rest/admin/__init__.py

synapse/rest/admin/users.py

synapse/storage/databases/main/pusher.py

synapse/storage/databases/main/registration.py

tests/rest/admin/test_user.py

tests/rest/client/test_shadow_banned.py