babel-traverse: Make the type of NodePath.type include null if the NodePath can contain a null node
babel-traverse: Make the type of NodePath.type include null if the NodePath can contain a null node

markogresak/DefinitelyTyped,borisyankov/DefinitelyTyped,borisyankov/DefinitelyTyped,magny/DefinitelyTyped,AgentME/DefinitelyTyped,georgemarshall/DefinitelyTyped,AgentME/DefinitelyTyped,dsebastien/DefinitelyTyped,AgentME/DefinitelyTyped,mcliment/DefinitelyTyped,georgemarshall/DefinitelyTyped,magny/DefinitelyTyped,georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,georgemarshall/DefinitelyTyped,AgentME/DefinitelyTyped