Add option to locally run HTMLProofer

[nickspaargaren]

What

This PR adds the option to locally run HTMLProofer. With the Python upgrade #2271 I ran into a problem with the html generation. This makes it easier to run the check without waiting for the Github actions to finish.

How to test

1. Check out this branch
2. Open VSCode and (Re)open in container. Or use: >Dev Containers: Reopen in Container
3. Wait for the container build to finish.
4. Use cd docs/ to navigate to the docs folder
5. Run make html to generate the html inside docs/_build
6. Use cd ../ to navigate back to the root folder
7. Run the htmlproofer command used in https://github.com/writethedocs/www/blob/main/.github/workflows/ubuntu.yml
   • htmlproofer --ignore-files "/404/,/2013/,/2014/,/2015/,/2016/,/2017/,/search\/index.html/" --allow-hash-href=true --enforce-https=false --ignore-missing-alt=true --disable-external=true docs/_build/html
8. Make sure the command can be run and checks for html warnings.

TODO

• Make sure Github actions pass with new ruby/setup-ruby action.

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📚 Documentation preview 📚: https://writethedocs-www--2285.org.readthedocs.build/

[plaindocs]

I'd be open to moving the htmlproofer link check out into external config or script to make it easier to run both locally and in CI.

The issue I ran into when running locally was that there are a lot of links like "/site-map/" which fail locally, and we'd have to figure out a way to address those. Or run it against a locally running server. 🤷‍♂️ Also a load of options which are valid in CI aren't locally (also probably a different version thing).

This part of the tool chain is really not a joy.

[nickspaargaren]

I'd be open to moving the htmlproofer link check out into external config or script to make it easier to run both locally and in CI.

The issue I ran into when running locally was that there are a lot of links like "/site-map/" which fail locally, and we'd have to figure out a way to address those. Or run it against a locally running server. 🤷‍♂️ Also a load of options which are valid in CI aren't locally (also probably a different version thing).

This part of the tool chain is really not a joy.

I saw this also locally. Maybe this is something we can fix later if the sphinx-ubuntu passes?

My secondary goal is to keep the htmlproofer updated with dependabot as well. At first i thought it was a bug that was fixed in a newer version of htmlproofer.

[plaindocs]

Probably :p - sorry for the mess

Suggested change

	- name: Install Ruby dependencies
	run: bundle install
	- name: Install Ruby dependencies
	run: bundle install