Code-generators should provide a way to "bundle" renaming

[rrousselGit]

Reopening #56764 (comment) as I don't think it should've been closed.

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Hello!
This is similar to #56518, but for another core IDE functionality: Renaming.

One way code-generators often work is by generating a new identifier, based on a user-defined identifier.
Like @example class UserDefined vs userDefinedGenerated, where the latter is generated based on a string transformation of the former.

The problem is, renaming renaming one of the two identifiers won't rename the other.

• Renaming @example class UserDefined will correctly update the generate code, but any existing reference to userDefinedGenerated will stay unchanged. Users will then have to modify those by hand ; which can be very tedious and error prone.
• Renaming userDefinedGenerated will not update UserDefined ; which means re-generating the code will revert our rename.

It would be great for the IDE to be able to rename both the generated and user-defined identifiers at once.

[dart-github-bot]

Summary: Code generators don't automatically update both user-defined and generated identifiers when one is renamed, requiring manual updates and causing inconsistencies. A solution to bundle renaming of both is requested.