Prevent @file annotations from creeping back into the codebase

We can't apply this to all files, we only want it to apply to something like */src/*.php but not sure how to integrate this with the existing sniffs for @inheritdoc, though maybe we can limit those as well.

This is covered by the rule <rule ref="Drupal.Commenting.FileComment"/> which is enabled in core. The files that are changed in the parent issue are missed because they have an additional class in the file. A complete explanation is in the Coding Standards issue filed to address this, #2735143: @file doc blocks for test classes with an additional class in the file → .

I think we need to postpone this until that is resolved and eventually Coder works for files with multiple classes.