Merge pull request #7188 from rodrigoflores/master

Documentation Fix: Pointing the case when no dependent option is given to a association method

activerecord/lib/active_record/associations.rb

@@ -941,7 +941,8 @@ def association_instance_set(name, association)
     #
     # The <tt>:dependent</tt> option can have different values which specify how the deletion
     # is done. For more information, see the documentation for this option on the different
-    # specific association types.
+    # specific association types. When no option is given, the behaviour is to do nothing
+    # with the associated records when destroying a record.
     #
     # === Delete or destroy?
     #