Update Transpiler

Transpiler.md

@@ -30,8 +30,10 @@ Features
 - Automatic string conversion of number/string add binary expressions `n+s` to `str(n)+s`
 
 ### **C# Delegates/GDScript Callable**
-- rewrite to not-nullable type
-- null-initializers from `null` to `Callable()`
+- add call invocation `callable(x)` to `callable.call( x )`
+- rewrite to not-nullable type with
+- declaration null-initializers from `null` to `Callable()`
+- variable null-initializers from `null` to `Callable()`
 - null-comparisons from `c == null` to `c == null || c.is_null()`
 
 ### **Math**