patch 8.2.0149: maintaining a Vim9 branch separately is more work

Problem:    Maintaining a Vim9 branch separately is more work.
Solution:   Merge the Vim9 script changes.
diff --git a/src/dict.c b/src/dict.c
index f3f3521..2ff4ae3 100644
--- a/src/dict.c
+++ b/src/dict.c
@@ -826,7 +826,7 @@
 
 	if (**arg != ':')
 	{
-	    semsg(_("E720: Missing colon in Dictionary: %s"), *arg);
+	    semsg(_(e_missing_dict_colon), *arg);
 	    clear_tv(&tvkey);
 	    goto failret;
 	}
@@ -853,7 +853,7 @@
 	    item = dict_find(d, key, -1);
 	    if (item != NULL)
 	    {
-		semsg(_("E721: Duplicate key in Dictionary: \"%s\""), key);
+		semsg(_(e_duplicate_key), key);
 		clear_tv(&tvkey);
 		clear_tv(&tv);
 		goto failret;
@@ -873,7 +873,7 @@
 	    break;
 	if (**arg != ',')
 	{
-	    semsg(_("E722: Missing comma in Dictionary: %s"), *arg);
+	    semsg(_(e_missing_dict_comma), *arg);
 	    goto failret;
 	}
 	*arg = skipwhite(*arg + 1);
@@ -881,7 +881,7 @@
 
     if (**arg != '}')
     {
-	semsg(_("E723: Missing end of Dictionary '}': %s"), *arg);
+	semsg(_(e_missing_dict_end), *arg);
 failret:
 	if (d != NULL)
 	    dict_free(d);