getNodeType( builder ) {

		if ( this.node === null ) {

			this.updateReference( builder );
			this.updateValue();

		}

		return this.node.getNodeType( builder );

	}
This method is overwritten since the node type is inferred from
the type of the reference node.

@param {NodeBuilder} builder - The current node builder.
@return {string} The node type.