Allow !replace to accept a scalar

This is the default merge behaviour, but simplifies using !replace because passing in a var that happens to evaluate to a scalar won't cause an issue anymore

app/Cfnpp/Functions.php

@@ -83,7 +83,10 @@ class Functions
 	 */
 	public function mf_replace(Node $original, Node $target, NodeFunction $function): ?Node
 	{
-		// TODO: Deal with nodefunctionvalue
+		if ($function instanceof NodeFunctionValue)
+		{
+			return new NodeValue(null, $target->hasName() ? $target->getName() : null, $function->getValue());
+		}
 
 		$replacement = new Node(null, $target->hasName() ? $target->getName() : null);
 		$replacement->setChildren($function->getChildren());