Mark Rails/LexicallyScopedActionFilter as unsafe

In the previous commit we documented an inheritance case in which the
Rails/LexicallyScopedActionFilter cop recommends unsafe edits that have
semantic implications.

Since not everyone will see the documentation examples, we're also
marking the cop as unsafe to signal that its recommendations should be
treated carefully.

CHANGELOG.md

@@ -19,6 +19,7 @@
 
 ### Changes
 
+* [#6854](https://github.com/rubocop-hq/rubocop/pull/6854): Mark Rails/LexicallyScopedActionFilter as unsafe and document risks. ([@urbanautomaton][])
 * [#5977](https://github.com/rubocop-hq/rubocop/issues/5977): Warn for Performance Cops. ([@koic][])
 * [#6637](https://github.com/rubocop-hq/rubocop/issues/6637): Move `LstripRstrip` from `Performance` to `Style` department and rename it to `Strip`. ([@anuja-joshi][])
 

config/default.yml

@@ -2445,6 +2445,7 @@ Rails/LexicallyScopedActionFilter:
   Description: "Checks that methods specified in the filter's `only` or `except` options are explicitly defined in the controller."
   StyleGuide: 'https://github.com/rubocop-hq/rails-style-guide#lexically-scoped-action-filter'
   Enabled: true
+  Safe: false
   VersionAdded: '0.52'
   Include:
     - app/controllers/**/*.rb

manual/cops_rails.md

@@ -1164,7 +1164,7 @@ Include | `app/models/**/*.rb` | Array
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
 --- | --- | --- | --- | ---
-Enabled | Yes | No | 0.52 | -
+Enabled | No | No | 0.52 | -
 
 This cop checks that methods specified in the filter's `only` or
 `except` options are defined within the same class or module.