Apply suggestions from code review

Co-authored-by: Jia Rong Yee <28086837+fourjr@users.noreply.github.com>

Author: Jerrie-Aries

cogs/utility.py

@@ -690,17 +690,17 @@ async def mention(self, ctx, *mention: Union[discord.Role, discord.Member, str])
         elif (
             len(mention) == 1
             and isinstance(mention[0], str)
-            and mention[0] in ["disable", "reset"]
+            and mention[0].lower() in ["disable", "reset"]
         ):
-            option = mention[0]
+            option = mention[0].lower()
             if option == "disable":
                 embed = discord.Embed(
                     description=f"Disabled mention on thread creation.", color=self.bot.main_color,
                 )
                 self.bot.config["mention"] = None
             else:
                 embed = discord.Embed(
-                    description="`mention` had been reset to default.", color=self.bot.main_color,
+                    description="`mention` is reset to default.", color=self.bot.main_color,
                 )
                 self.bot.config.remove("mention")
             await self.bot.config.update()