update cop description and examples

Author: masato-bkn

lib/rubocop/cop/rails/redundant_active_record_all_method.rb

@@ -6,18 +6,20 @@ module Rails
       # Detect redundant `all` used as a receiver for Active Record query methods.
       #
       # @safety
-      #   This cop is unsafe if the receiver object is not an Active Record object.
+      #   This cop is unsafe for autocorrection if the receiver for `all` is not an Active Record object.
       #
       # @example
       #   # bad
-      #   User.all.order(:created_at)
       #   User.all.find(id)
-      #   User.all.where(id: ids)
+      #   User.all.order(:created_at)
+      #   users.all.where(id: ids)
+      #   user.articles.all.order(:created_at)
       #
       #   # good
-      #   User.order(:created_at)
       #   User.find(id)
-      #   User.where(id: ids)
+      #   User.order(:created_at)
+      #   users.where(id: ids)
+      #   user.articles.order(:created_at)
       class RedundantActiveRecordAllMethod < Base
         include ActiveRecordHelper
         extend AutoCorrector