patch 8.2.1468: Vim9: invalid error for missing white space

Problem:    Vim9: invalid error for missing white space.
Solution:   Don't skip over white space after index. (closes #6718)
diff --git a/src/eval.c b/src/eval.c
index 37ed515..3c4a8c5 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3624,7 +3624,7 @@
 		clear_tv(&var2);
 	    return FAIL;
 	}
-	*arg = skipwhite(*arg + 1);	// skip the ']'
+	*arg = *arg + 1;	// skip over the ']'
     }
 
     if (evaluate)