The major changes here are:

1. Inherit from `RuboCop::Cop::Base`, not `RuboCop::Cop::Cop`.
2. New auto-correction style - `extend RuboCop::Cop::AutoCorrector`,
   pass a block to `add_offense` rather than defining an `autocorrect`
   method.
3. `add_offense` no longer takes a `location` keyword argument.
4. Specs should not set `subject(:cop)` as that will be done
   automatically, and will use the config correctly.

The property had been renamed to `_deprecated_feature_flag` earlier.

This change removes it altogether and all code that was supporting it.

https://gitlab.com/gitlab-org/gitlab/-/issues/369202

Mutations are considered the same abstraction level as the REST API.

Signed-off-by: Rémy Coutable <remy@rymai.me>

This reverts commit 37915bb5, reversing
changes made to 16ecd9f6.

`(const nil :Foo)` vs `(const nil? :Foo)`

These Cops enforces the code reuse rules as defined in merge request
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21254.

These Cops enforces the code reuse rules as defined in merge request
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21254.