language: Remove inline menus

Inline menus didn't work anyway--menus have to be referenced by ID
(though, curiously, you *can* put the <menu> within the <property> tag
and immediately reference it--but that's a hack, and not what
blueprint-compiler was doing).

blueprintcompiler/language/gobject_property.py

@@ -53,7 +53,7 @@ class Property(AstNode):
             UseIdent("name"),
             ":",
             AnyOf(
-                OBJECT_HOOKS,
+                Object,
                 VALUE_HOOKS,
             ).expected("a value"),
         ),