Fix #11366

[embray]

This fixes #11366 by adding two things:

• Adds astropy-dev to the intersphinx mappings. This can be used now anywhere in the Astropy docs to link to docs in the
  current development version (but particularly this is useful for linking to the Developer Guide since it now lives only in the
  development version).

• When building the development version of the docs, astropy-dev: references are automatically resolved in the "normal" manner
  as though the astropy-dev: prefix weren't there, so it avoids using the intersphinx mapping in this case.

[embray]

Also with this change, once #11621 is done we won't need the Jinja templating at all anymore.

@pllim It seems the "Check PR change log" action complains even if the "Affects-dev" label is used.

[embray]

I just realized there are some other "if is_development" sections in install.rst that were added since I last worked on this. So I'll go back to using the Jinja templating just for those sections for now, and worry about reworking those parts as part of #11621

[pllim]

It seems the "Check PR change log" action complains even if the "Affects-dev" label is used.

towncrier check doesn't care about "Affects-dev" -- Maybe @Cadair can comment.

[pllim]

p.s. Saw your pings for reviews. It is on my todo list!

[Cadair]

It seems the "Check PR change log" action complains even if the "Affects-dev" label is used.

towncrier check doesn't care about "Affects-dev" -- Maybe @Cadair can comment.

Huh, why would it?

[pllim]

@Cadair , because astropy-bot old-style change log check recognized it, though it was a very astropy specific thing.

@embray , if you feel strongly about adding back "Affects-dev" for the change log check, I can add that logic into https://github.com/pllim/actions-towncrier-changelog but the change will likely be lost when/if we switch back to using https://github.com/OpenAstronomy/baldrick/blob/master/baldrick/plugins/github_towncrier_changelog.py . For now, only no-changelog-entry-needed will skip the check.

[Cadair]

What did it do?!

[pllim]

Full logic is here, but it probably won't apply as-is with new change log system: https://github.com/astropy/astropy-bot/blob/main/astropy_bot/changelog_checker.py

[pllim]

Looks fine, except for a minor typo.

I am testing the "stable" build at #11652

[pllim]

And for my own future reference, in this PR, https://astropy--11622.org.readthedocs.build/en/11622/install.html resolved the link for "virtualenv" to https://astropy--11622.org.readthedocs.build/en/11622/development/workflow/virtual_pythons.html#virtual-envs , as expected.

[embray]

@pllim Fixed! Thanks for the confirm.

[pllim]

LGTM. It's like magic. Thanks!