Show number of participants in currently joined channel in tray icon

[ellegance]

Context
Showing number of participants in channel in tray icon might be useful in following cases:

1. You see that you are not alone in channel, it makes sense to start speaking (number >1).
2. You constantly talk to for ex. 5 people and expect that they are all present, and you see number 5 in tray without need to open Mumble window.
3. It would be great to show both number of participants and talking status (which is already implemented) at the same time.

[Krzmbrzl]

For the time being you might also be interested in the new TalkingUI that found its way into Mumble 1.4.0.
It is described in the changelog for the first dev snapshot of it

[Krzmbrzl]

Closing this as infeasible as

you can not really add text to the tray icon. So you would have to use the themed status icon you want to display and - at runtime - add some numbers to it, which seems... cumbersome

to which I have to agree

Source: #6466 (comment)