Add forward slash to LITERAL_REGEX

The forward slash character has no special meaning when it appears in a
regex. This will let `Performance/StartWith` and `Performance/EndWith`
correct code like the following:

    path =~ %r{/\z}

To:

    path.end_with?('/')

CHANGELOG.md

@@ -9,6 +9,7 @@
 * [#7449](https://github.com/rubocop-hq/rubocop/pull/7449): Make `Style/IfUnlessModifier` respect `rubocop:disable` comments for `Metrics/LineLength`. ([@jonas054][])
 * [#7442](https://github.com/rubocop-hq/rubocop/issues/7442): Fix an incorrect autocorrect for `Style/SafeNavigation` when an object check followed by a method call with a comment at EOL. ([@koic][])
 * [#7434](https://github.com/rubocop-hq/rubocop/issues/7434): Fix an incorrect autocorrect for `Style/MultilineWhenThen` when the body of `when` branch starts with `then`. ([@koic][])
+* [#7464](https://github.com/rubocop-hq/rubocop/pull/7464): Let `Performance/StartWith` and `Performance/EndWith` correct regexes that contain forward slashes. ([@eugeneius][])
 
 ### Changes
 

lib/rubocop/cop/util.rb

@@ -9,7 +9,7 @@ module Util
       # Match literal regex characters, not including anchors, character
       # classes, alternatives, groups, repetitions, references, etc
       LITERAL_REGEX =
-        /[\w\s\-,"'!#%&<>=;:`~]|\\[^AbBdDgGhHkpPRwWXsSzZ0-9]/.freeze
+        %r{[\w\s\-,"'!#%&<>=;:`~/]|\\[^AbBdDgGhHkpPRwWXsSzZ0-9]}.freeze
 
       module_function