sage.{calculus,functions,numerical,symbolic}: Docstring/doctest cosmetics, # needs

[mkoeppe]

Cherry-picked from #35095.

📝 Checklist

• The title is concise and informative.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[github-actions]

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[DaveWitteMorris]

I'm sorry, but I can't review this, because I don't understand modularization.

[kwankyu]

I'm sorry, but I can't review this, because I don't understand modularization.

@mkoeppe For this business of maintaining the "# needs" or "# optional" tags, I think that it should be obvious to a PR author how to modify or add or delete those tags. I guess that "Test modularized distributions" of "B&T" would (could) annotate "Files changed" with appropriate messages on how to modify them. If I am right, is it working now or are you working for it to work?

[kwankyu]

Otherwise, lgtm.

[mkoeppe]

For this business of maintaining the "# needs" or "# optional" tags, I think that it should be obvious to a PR author how to modify or add or delete those tags. I guess that "Test modularized distributions" of "B&T" would (could) annotate "Files changed" with appropriate messages on how to modify them. If I am right, is it working now or are you working for it to work?

This can only be done after the distributions in #35095 have been merged into develop.
In the current branch, these tags just cannot be tested yet.

[kwankyu]

I see. Thanks.

[mkoeppe]

Thank you!

[vbraun]

fail, see CI