Custom Command Examples Broken

[Crocatowa]

What Red version are you using?

3.5.1

Cog name

Customcom

Command name

!say Pete and Repeat

What did you expect to happen?

Bot should echo "Pete and Repeat"

[p]customcom add simple say {0}
[p]say Pete and Repeat
(In my case, !customcom.... etc)

What actually happened?

Nothing on the Discord side, this error in the logs:

[ERROR] discord.client: Ignoring exception in on_message_without_command
Traceback (most recent call last):
  File "/data/venv/lib/python3.11/site-packages/discord/client.py", line 441, in _run_event
    await coro(*args, **kwargs)
  File "/data/venv/lib/python3.11/site-packages/redbot/cogs/customcom/customcom.py", line 679, in on_message_without_command
    await self.bot.invoke(ctx)
  File "/data/venv/lib/python3.11/site-packages/discord/ext/commands/bot.py", line 1350, in invoke
    await ctx.command.invoke(ctx)
  File "/data/venv/lib/python3.11/site-packages/discord/ext/commands/core.py", line 1015, in invoke
    await self.prepare(ctx)
  File "/data/venv/lib/python3.11/site-packages/redbot/core/commands/commands.py", line 482, in prepare
    await self._parse_arguments(ctx)
  File "/data/venv/lib/python3.11/site-packages/discord/ext/commands/core.py", line 847, in _parse_arguments
    kwargs[name] = await self.transform(ctx, param, attachments)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/venv/lib/python3.11/site-packages/discord/ext/commands/core.py", line 647, in transform
    converter = param.converter
                ^^^^^^^^^^^^^^^
AttributeError: 'Parameter' object has no attribute 'converter'

How can we reproduce this error?

1. Fresh Install of Red 3.5.1 with Python 3.11
2. !customcom add simple say {0}
3. !say Pete and Repeat
4. Bot doesn't respond in Discord and Error is posted to the logs

Anything else?

I was following the examples in https://docs.discord.red/en/stable/cog_customcom.html
The only example that did work was the one for the avatar image