Allow more than 2 pinned messages in a chat

Firstly, I'm not a developer, and I know nothing of this site's code base. Having said that, the ability to pin messages so that certain pieces of information are retained in memory no matter how far the conversation progresses is very useful.

Unfortunately the ability to pin only 2 messages is not so useful and can be a bit of a hindrance for longer conversations where there are multiple messages that I'd like the AI to remember.

I don't know if there is a practical limit, but in my mind, we should be able to pin up to 5 messages per chat.