Silently fail if an invoked command doesn't exist

Author: ChrisLovering

bot/exts/utils/error_handler.py

@@ -51,6 +51,9 @@ async def on_command_error(self, ctx: Context, e: errors.CommandError) -> None:
             await self.handle_check_failure(ctx, e)
         elif isinstance(e, errors.CommandOnCooldown):
             await ctx.send(e)
+        elif isinstance(e, errors.CommandNotFound):
+            # Silently fail if command doesn't exist
+            return
         elif not isinstance(e, errors.DisabledCommand):
             # MaxConcurrencyReached, ExtensionError
             await self.handle_unexpected_error(ctx, e)