Add references to TypeScript in documentation where appropriate, such
as in example bash commands and discussions of the file structure.
Add a new section to the Reading List with TypeScript resources.
Also update `.editorconfig` to support ".ts" files.
Fix part of #12000.
Sphinx/ReadTheDocs supports automatically translating links written as
to `.md` files to point to the corresponding `.html` files, so this
migration does not change the resulting HTML output in ReadTheDocs.
But it does fix apparent broken links on GitHub.
This doesn't prevent people from reading the documentation on GitHub
(so doesn't mitigate the fact that some rtd-specific syntax does not
render properly on GH), but it will prevent us from getting erroneous
issues reported about the hyperlinks not working.
Fixes: #11087.
help.github.com seems to have a bug where HEAD on a redirected page
returns 404. This causes tools/test-documentation to fail. Fix it by
skipping the redirects.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
The testing section is more appropriate, since it's fundamentally part
of our CI system.
While we're at it, fix the fact that we were linking to GitHub, not
ReadTheDocs, in the run-mypy output.