ansible-doc: restore role attributes

[felixfontein]

SUMMARY

Fixes #82639.

ISSUE TYPE

• Bugfix Pull Request

[sivel]

@felixfontein we've had a discussion around re-adding this unexpected feature. Since we didn't have any documentation explaining that unintended features could be removed without deprecation, we would be willing to potentially re-accept this.

However, the stipulation being that, it would be merged with an immediate deprecation for future removal.

With the above being said, do you feel it would be useful to re-add this feature to start immediately preparing to stop using it, or should we just leave it removed?

[felixfontein]

@sivel while I still disagree that it should be removed/deprecated at all, having a proper deprecation period is better than just removing it.

[s-hertel]

I added a deprecation warning so this can be merged, hopefully this looks okay:

[DEPRECATION WARNING]: The role testns.testcol.testrole's argument spec alternate contains the key "attributes", which will not be displayed by ansible-doc in the future. This was unintentionally allowed when plugin attributes were
added, but the feature does not map well to role argument specs. This feature will be removed from ansible-core in version 2.20. Deprecation warnings can be disabled by setting deprecation_warnings=False in ansible.cfg.

[felixfontein]

This also does need a deprecation docs fragment now. @s-hertel do you want to add that as well, or should I?

[s-hertel]

Since there was no changelog/documentation for the accidental feature, I didn't think it needed one, but if you want to add one feel free, I'm out until Monday.

[bcoca]

I would add a changelog since it includes a deprecation now

[felixfontein]

@s-hertel @bcoca thanks for reviewing and merging!