neo: Add `MAttributeDef.static_type` in the graph.

Signed-off-by: Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>
Merge: neo: Add `MAttributeDef.static_type` in the graph.

Pull-Request: #838
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>
Reviewed-by: Jean Privat <jean@pryen.org>