Update throwFunction.md

Author: DeveloperTryingToCodeLikeOtherOfThem

docs/throwFunction.md

@@ -1,6 +1,9 @@
 ## Throw function
 
 Throws a value written in the problems pane, similar to the throw syntax. 
+```
+ pxt.throwValue(null);
+```
 
 The difference is that the function is the core of the syntax in the MakeCode environment.