Add typing syntax

modules/gdscript/gdscript_tokenizer.h

@@ -106,6 +106,8 @@ public:
 		TK_PR_SETGET,
 		TK_PR_CONST,
 		TK_PR_VAR,
+		TK_PR_AS,
+		TK_PR_VOID,
 		TK_PR_ENUM,
 		TK_PR_PRELOAD,
 		TK_PR_ASSERT,
@@ -131,6 +133,7 @@ public:
 		TK_QUESTION_MARK,
 		TK_COLON,
 		TK_DOLLAR,
+		TK_FORWARD_ARROW,
 		TK_NEWLINE,
 		TK_CONST_PI,
 		TK_CONST_TAU,