patch 8.2.3177: Vim9: can not use "for _ in expr" at script level

Problem:    Vim9: can not use "for _ in expr" at script level.
Solution:   Skip assignment if the loop variable is "_".

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3177,
 /**/
     3176,
 /**/