patch 8.2.2034: Vim9: list unpack in for statement not compiled yet

Problem:    Vim9: list unpack in for statement not compiled yet.
Solution:   Compile list unpack. (closes #7345)
diff --git a/src/vim9.h b/src/vim9.h
index 9685b9d..1368b38 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -146,6 +146,7 @@
     ISN_CMDMOD,	    // set cmdmod
     ISN_CMDMOD_REV, // undo ISN_CMDMOD
 
+    ISN_UNPACK,	    // unpack list into items, uses isn_arg.unpack
     ISN_SHUFFLE,    // move item on stack up or down
     ISN_DROP	    // pop stack and discard value
 } isntype_T;
@@ -284,6 +285,12 @@
     cmdmod_T	*cf_cmdmod;	// allocated
 } cmod_T;
 
+// arguments to ISN_UNPACK
+typedef struct {
+    int		unp_count;	// number of items to produce
+    int		unp_semicolon;	// last item gets list of remainder
+} unpack_T;
+
 /*
  * Instruction
  */
@@ -321,6 +328,7 @@
 	shuffle_T	    shuffle;
 	put_T		    put;
 	cmod_T		    cmdmod;
+	unpack_T	    unpack;
     } isn_arg;
 };