Add vale linter bot

[santos22]

Fixes #5876

😄 I was inspired by the following projects since they had vale set up:

• https://github.com/writethedocs/www
• https://github.com/linode/docs

TODO:

• Fix incorrect usages of "Read the Docs"
• Fix legacy misspelling
• Fix can can repetition

[santos22]

Interesting. The new build job should've failed like it did locally.

[santos22]

Build is now failing! Can follow-up and fix the incorrect usages of "Read the Docs" after someone sees this to confirm that it does work 👍

https://travis-ci.org/github/readthedocs/readthedocs.org/jobs/691165858

[santos22]

The following can be added to .vale.ini.

Vale.Spelling = YES
Vale.Repetition = YES

I've attached some screenshots on what this looks like but did not include in this pull request. There's some weirdness with the Spelling rule where it doesn't recognize terms like MkDocs, Conda, etc. Looks like we can add an text file with terms to ignore (https://errata-ai.github.io/vale/styles/#spelling).

The errors for repetition are because of reStructuredText headings and that same word coming right after. There was a valid repetition caught that can be fixed as part of this PR.

Spelling

Repetition

For most Python dependencies, you can can specify a requirements file...

Source: https://github.com/readthedocs/readthedocs.org/blob/master/docs/faq.rst#my-documentation-requires-additional-dependencies

[santos22]

Thoughts @humitos @stsewd?

[ericholscher]

This seems useful, if it doesn't add too much time to our builds. Our CI is already really slow, but I could see this being useful for our docs.

[ericholscher]

I think we want to enable this usage in some places, but the above rule makes sense to me.

[santos22]

It looks like we can disable and enable with the following markup comments:

Read The Docs

.. vale off

Read The Docs

.. vale on

Read The Docs

So in that example, an error would be thrown for text before .. vale off and for text after .. vale on.

Source: https://errata-ai.gitbook.io/vale/getting-started/markup#restructuredtext

[santos22]

If the linter is not needed at this point in time, I can re-purpose this PR to fix the incorrect usages of "Read the Docs" and the spelling and repetition errors.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.