code_style: more formatting

docs/code_style.rst

 - Everything should comply with PEP8. Code should pass
   ``pep8 --max-line-length=100`` without any warnings.
-- NEVER tabs. 4 spaces to indent.
-- Max line width: 79 chars (with flexibility to overflow by a "few chars" if
+
+- **Indenting**:
+
+  - NEVER tabs. 4 spaces to indent.
+
+  - follow PEP8; either hanging indent or multiline-visual indent depending
+    on the size and shape of the arguments and what makes more sense to the
+    author. In other words, both this::
+
+      print("I am a fish %s" % "moo")
+
+    and this::
+
+      print("I am a fish %s" %
+            "moo")
+
+      and this::
+
+        print(
+            "I am a fish %s" %
+            "moo",
+        )
+
+    ...are valid, although given each one takes up 2x more vertical space than
+    the previous, it's up to the author's discretion as to which layout makes
+    most sense for their function invocation.  (e.g. if they want to add
+    comments per-argument, or put expressions in the arguments, or group
+    related arguments together, or want to deliberately extend or preserve
+    vertical/horizontal space)
+
+- **Line length**:
+
+  Max line length is 79 chars (with flexibility to overflow by a "few chars" if
   the overflowing content is not semantically significant and avoids an
   explosion of vertical whitespace).
-- Use camel case for class and type names
-- Use underscores for functions and variables.
-- Use double quotes.
-- Use parentheses instead of '\\' for line continuation where ever possible
-  (which is pretty much everywhere)
-- There should be max a single new line between:
+
+  Use parentheses instead of ``\`` for line continuation where ever possible
+  (which is pretty much everywhere).
+
+- **Naming**:
+
+  - Use camel case for class and type names
+  - Use underscores for functions and variables.
+
+- Use double quotes ``"foo"`` rather than single quotes ``'foo'``.
+
+- **Blank lines**:
+
+  - There should be max a single new line between:
+
     - statements
     - functions in a class
-- There should be two new lines between:
-    - definitions in a module (e.g., between different classes)
-- There should be spaces where spaces should be and not where there shouldn't be:
-    - a single space after a comma
-    - a single space before and after for '=' when used as assignment
-    - no spaces before and after for '=' for default values and keyword arguments.
-- Indenting must follow PEP8; either hanging indent or multiline-visual indent
-  depending on the size and shape of the arguments and what makes more sense to
-  the author. In other words, both this::
 
-    print("I am a fish %s" % "moo")
+  - There should be two new lines between:
 
-  and this::
-
-    print("I am a fish %s" %
-          "moo")
+    - definitions in a module (e.g., between different classes)
 
-  and this::
+- **Whitespace**:
 
-    print(
-        "I am a fish %s" %
-        "moo"
-    )
+  There should be spaces where spaces should be and not where there shouldn't
+  be:
 
-  ...are valid, although given each one takes up 2x more vertical space than
-  the previous, it's up to the author's discretion as to which layout makes most
-  sense for their function invocation.  (e.g. if they want to add comments
-  per-argument, or put expressions in the arguments, or group related arguments
-  together, or want to deliberately extend or preserve vertical/horizontal
-  space)
+  - a single space after a comma
+  - a single space before and after for '=' when used as assignment
+  - no spaces before and after for '=' for default values and keyword arguments.
 
-- Comments should follow the `google code style
+- **Comments**: should follow the `google code style
   <http://google.github.io/styleguide/pyguide.html?showone=Comments#Comments>`_.
   This is so that we can generate documentation with `sphinx
   <http://sphinxcontrib-napoleon.readthedocs.org/en/latest/>`_. See the