Module Output Deprecation through structural analysis

[DanielMSchmidt]

This is the younger sibling of #37795 where instead of using deprecation marks and therefore working on values we reason about the structure (so looking at all references written in the config instead of only the ones actually used in the config).

I reconstructed the issue @dbanck and I ran into a year ago: module.mod[*].old is failing us. We need at least module.mod as a reference and [*].old as the remainder to piece it together as a module call output.
During langrefs.ReferencesIn* we call expr.Variables() (expr being hcl.Expression) but HCL seems to stop the parsing after module.mod which means we need to change HCL to include the remainder of the reference so we can continue.

Fixes #

Target Release

1.15.x

Rollback Plan

• If a change needs to be reverted, we will roll out an update to the code within 7 days.

Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.

CHANGELOG entry

• This change is user-facing and I added a changelog entry.
• This change is not user-facing.

[github-actions]

The equivalence tests will be updated. Please verify the changes here.