go: Enforce length limit on vote

GoBot/command_vote.go

@@ -106,6 +106,10 @@ func voteSuggestion(s *discordgo.Session, m *discordgo.MessageCreate) {
 		sendPrivateMessage(s, m.Author.ID, "请提供更多资料。\nPlease provide more information.")
 		return
 	}
+	if len(args[1]) > 500 {
+		sendPrivateMessage(s, m.Author.ID, "你投票的内容过长了。请使用少过500个字符。\nYour vote is too long. Please use a maximum of 500 characters.")
+		return
+	}
 
 	switch args[0] {
 	case "custom":