Utilities/Sphinx: Fix QtHelp generator identifiers

Add missinge entry in `create_identifiers.py` helper.

Utilities/Sphinx/create_identifiers.py

@@ -22,6 +22,7 @@ for line in lines:
 
   mapping = (("command", "command"),
              ("variable", "variable"),
+             ("generator", "generator"),
              ("target property", "prop_tgt"),
              ("test property", "prop_test"),
              ("source file property", "prop_sf"),