patch 8.2.3054: Vim9: unpack assignment using "_" after semicolon fails

Problem:    Vim9: unpack assignment using "_" after semicolon fails.
Solution:   Drop the expression result. (closes #8453)
diff --git a/src/errors.h b/src/errors.h
index b4cf8ae..a4dcea2 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -318,7 +318,7 @@
 EXTERN char e_missing_matching_bracket_after_dict_key[]
 	INIT(= N_("E1139: Missing matching bracket after dict key"));
 EXTERN char e_for_argument_must_be_sequence_of_lists[]
-	INIT(= N_("E1140: For argument must be a sequence of lists"));
+	INIT(= N_("E1140: :for argument must be a sequence of lists"));
 EXTERN char e_indexable_type_required[]
 	INIT(= N_("E1141: Indexable type required"));
 EXTERN char e_non_empty_string_required[]