[Feature] Toggle direct messages

[Folas1337]

Proposed Feature Description:

I'd like to be able to use /msg <user> with no message which would then toggle writing to that person and no matter what message I put in chat afterwards, it'll be sent to that person. This way I don't always have to start my messages with /r which people just forget quite often.

Proposed Feature Functionality:

Basically we make the message part of the /msg command optional and without it, it will toggle the message to that person.
Just have to make sure that if this person logs off, I can still toggle back to global chat somehow, most intuitive would be to use /msg <user> again and just not check if that user is still logged on or not but you might have to help me out with what's technically possible.

Alternatively we can rely on /global or /ch global which would be fine for me as well.