Add HTTP resources to TOC

[sevdog]

This PR adds the methods to handle TOC (table of content) generation which can be used by themes like furo to build a page-level-toc.

This can simplify nagivation in pages when there are many HTTP endpoints.

[stevepiercy]

@sevdog does this generate the right-hand "On this page" navigation, such as this in Furo?

If so, how is that different from the current implementation at https://sphinxcontrib-httpdomain.readthedocs.io/en/stable/index.html?

To merge this PR, it needs the following:

• rebase on main
• change log entry into doc/changelog.rst
• documentation in doc/index.rst about what this does or supports differently than the current implementation

Please let me know. Thank you!

[read-the-docs-community]

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📚 sphinxcontrib-httpdomain | 🛠️ Build #31194038 | 📁 Comparing ba685ee against latest (8fcfb8e)

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[sevdog]

Hi @stevepiercy, you are right that is what I am achieving to get, to show also endpoints in the TOC. Because without implementing those methods sphinx will not put them in the TOC (and by default the returns empty elements).

I have updated the PR and the code by also adding a specific flag to turn on this change.

[stevepiercy]

This is a very nice and useful improvement. Thank you! I expanded the wording in the documentation and change log. Would you please take a look and let me know or just accept the suggestions?

[sevdog]

I just putted the changes with a single commit. I'm fine with the wording, thank you.

[stevepiercy]

Thank you! Will merge after CI passes. This will go into the a2 release. I'll try to get that out later today or tomorrow.