jump to the next unread DM / mention, keyboard shortcut

### Your use case

#### What would you like to do?
Using a keyboard short I would like to jump to the next unread message which is addressed to me (DM / mention / keyword in a room).

#### Why would you like to do it?
While I'm following many IRC channels I'm not often interested in others talk in the rooms. I'm mainly interested in the messages posted to me or mentioning me / keyword.

#### How would you like to achieve it?
A very simple keyboard short would be welcome. E.g. I'm used to use ALT+A in _the lounge_ client, that is very convenient shortcut easily reachable by one hand.

### Have you considered any alternatives?

It seems to be possible to achieve that by mouse clicking in the section / group number badge but that's not so user friendly for keyboard oriented people.

### Additional context

Currently, there's only ALT+SHIFT+UP/DOWN for jumping to unread DM / room which ignores the the fact whether I was mentioned in a room or not so I need to go through lots of unrelated stuff.