Tweak the doc for Lint/RedundantDirGlob cop

Indentation is required to generate the `Safety` section.
https://docs.rubocop.org/rubocop/1.26/cops_lint.html#lintredundantdirglobsort

lib/rubocop/cop/lint/redundant_dir_glob_sort.rb

@@ -7,9 +7,9 @@ module Lint
       # This cop checks for redundant `sort` method to `Dir.glob` and `Dir[]`.
       #
       # @safety
-      # This cop is unsafe, in case of having a file and a directory with
-      # identical names, since directory will be loaded before the file, which
-      # will break `exe/files.rb` that rely on `exe.rb` file.
+      #   This cop is unsafe, in case of having a file and a directory with
+      #   identical names, since directory will be loaded before the file, which
+      #   will break `exe/files.rb` that rely on `exe.rb` file.
       #
       # @example
       #