[V3] Set token command fix (#1449)

* [V3] Add set token command

* DM check

* warning message + delete if token isn't send in DM

* Update string formatting

* fix condition invertion

redbot/core/core_commands.py

@@ -744,7 +744,8 @@ class Core:
     @checks.is_owner()
     async def token(self, ctx, token: str):
         """Change bot token."""
-        if not not isinstance(ctx.channel, discord.DMChannel):
+
+        if not isinstance(ctx.channel, discord.DMChannel):
             
             try:
                 await ctx.message.delete()