Help ReadTheDocs to better integrate with MkDocs

[pawamoy]

MkDocs 1.5 added a custom !relative tag. ReadTheDocs currently only handles !!python/name tags. Support was added in this PR: readthedocs/readthedocs.org#7507. Latest code can be found here:
https://github.com/readthedocs/readthedocs.org/blob/main/readthedocs/doc_builder/backends/mkdocs.py. As you can see the safe loader still only handles these tag. I guess it means that !relative tag are not supported, and upon re-dumping YAML, these values would simply be lost.

ReadTheDocs wants to find a way to better integrate with MkDocs, to avoid having to fake-implement custom tags just to inject configuration. See readthedocs/readthedocs.org#7844. Maybe we could discuss this here as well.

[humitos]

We are merging and deploying this PR today/tomorrow: readthedocs/readthedocs.org#11206 that removes the manipulation of the YAML file from Read the Docs.

Users should be able to use all the supported YAML syntax on Read the Docs after the deploy 🎉 . Thanks for all your support!

[pawamoy]

Great news @humitos! Congrats to the RTD team 🎉

[humitos]

Can this discussion be marked as solved now that people can use all the YAML syntax that MkDocs supports? Thanks.