PEP 8 whitespace cleanup. (#20783)

* PEP 8 E271 whitespace cleanup.
* PEP 8 W293 whitespace cleanup.
* Fix whitespace issue from recent PR.

lib/ansible/modules/system/group.py

@@ -302,7 +302,7 @@ class DarwinGroup(Group):
             (rc, out, err) = self.execute_command(cmd)
             return (rc, out, err)
         return (None, '', '')
-    
+
     def get_lowest_available_system_gid(self):
         # check for lowest available system gid (< 500)
         try: