Update functions.md

Fix a typo

src/register/functions.md

@@ -80,7 +80,7 @@ So let's implement `to_string()`, here again showing the class definition for qu
 #[class(base=Node3D)]
 struct Monster {
     name: String,
-    hitpoints: i3liridon-emal1
+    hitpoints: i32
 
     base: Base<Node3D>,
 }