patch 8.2.1900: Vim9: command modifiers do not work

Problem:    Vim9: command modifiers do not work.
Solution:   Make most command modifiers work.
diff --git a/src/vim9.h b/src/vim9.h
index 8056c60..60699f9 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -142,8 +142,8 @@
 
     ISN_PUT,	    // ":put", uses isn_arg.put
 
-    ISN_SILENT,	    // set msg_silent or emsg_silent if arg_number is non-zero
-    ISN_UNSILENT,   // undo ISN_SILENT
+    ISN_CMDMOD,	    // set cmdmod
+    ISN_CMDMOD_REV, // undo ISN_CMDMOD
 
     ISN_SHUFFLE,    // move item on stack up or down
     ISN_DROP	    // pop stack and discard value
@@ -278,6 +278,11 @@
     linenr_T	put_lnum;	// line number to put below
 } put_T;
 
+// arguments to ISN_CMDMOD
+typedef struct {
+    cmdmod_T	*cf_cmdmod;	// allocated
+} cmod_T;
+
 /*
  * Instruction
  */
@@ -314,6 +319,7 @@
 	checklen_T	    checklen;
 	shuffle_T	    shuffle;
 	put_T		    put;
+	cmod_T		    cmdmod;
     } isn_arg;
 };