patch 8.2.4099: Vim9: cannot use Vim9 syntax in mapping

Problem:    Vim9: cannot use Vim9 syntax in mapping.
Solution:   Add <ScriptCmd> to use the script context for a command.

src/misc2.c

@@ -1057,6 +1057,7 @@ static struct key_name_entry
     {K_CURSORHOLD,	(char_u *)"CursorHold"},
     {K_IGNORE,		(char_u *)"Ignore"},
     {K_COMMAND,		(char_u *)"Cmd"},
+    {K_SCRIPT_COMMAND,	(char_u *)"ScriptCmd"},
     {K_FOCUSGAINED,	(char_u *)"FocusGained"},
     {K_FOCUSLOST,	(char_u *)"FocusLost"},
     {0,			NULL}