AS3 pcode - Use Undefined as default keyword for value kind

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
+## [Unreleased]
+### Changed
+- AS3 pcode - Use Undefined as default keyword for value kind
+
 ## [13.0.1] - 2021-02-09
 ### Fixed
 - AS3 break loop in catch clause

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/ValueKind.java

@@ -197,7 +197,7 @@ public class ValueKind {
                 ret = "Null()";
                 break;
             case CONSTANT_Undefined:
-                ret = "Void()";
+                ret = "Undefined()"; //"Void()" is also synonym
                 break;
             case CONSTANT_Namespace:
             case CONSTANT_PackageInternalNs: