autosummary generator and templates should support module data (ie fields/constants)

[ben-spiller]

Is your feature request related to a problem? Please describe.
I want to use the autosummary_generate to automatically generate rst files for a large project. Some of my modules define data constants. I'm using a customized module.rst template to get the output just the way I want, but there is no way to include the module data in the output.

Describe the solution you'd like
autosummary_generate should support module data just as it currently support module classes/exceptions/functions, i.e. by providing a "data" variable containing a list of the data items defined in this module, which could be used with autodata or similar. This would need to be added in the generate_autosummary_content function of generate.py

Maybe the default autosummary module.rst template should display data fields (just like automodule does), but that's less pressing - the most important thing is to add it to the templating so that at least people can add it themselves if needed.

Describe alternatives you've considered
I tried using "members" as a workaround (since I figured any member that's not in functions/classes/exceptions must be data) however annoyingly/surprisingly members is implemented using dir(module) rather than the get_members() function all the others use, so bypasses the normal logic for deciding about private/non-private and direct members vs imported so includes far too much junk to be useful.
https://www.sphinx-doc.org/en/master/usage/extensions/autosummary.html

I can't see any extension hooks that would enable an enduser of sphinx to add this capability without forking/changing the autosummary extension itself

Additional context
(While we're at it, a list of submodules would be really nice too)

[tk0miya]

+1