It doesn't look like we need:
- `sphinx.ext.githubpages`
- `sphinx.ext.todo`
- `sphinx.ext.mathjax`
So I removed these and then sorted the list of extensions.
This commit mostly focuses on f-strings, collections, comprehensions,
and subscripts/slices.
I added intersphinx support to the sphinx config so I could link to
`ast.literal_eval`.
I exported BaseSimpleComp, since I felt it had some documentation value.
- Now that we're exporting everything from the top-level libcst package,
automodule makes a mess of things.
- While it does create more boilerplate, using autoclass/autofunction
instead of automodule gives us a lot more control over the order in
which nodes are presented, so we can group them by various categories.
This diff also exports BaseParenthesizableWhitespace, because nodes
refer to it by type, and so it's needed for documentation purposes.
Without this option, autodoc defaults to ordering all members of
modules and classes alphabetically.
While this is normally fine (and probably desirable), the ordering of
fields in dataclasses is significant, so we need to change this behavior
to preserve the original member ordering.
