Andrea Maria Piana 11de62749d Add unviewed mentions count
This commit add a field to count the unviewed mentions in a given chat.
The usage pattern is identical to `UnviewedMessagesCount`
2021-05-28 13:05:23 +02:00
..
2021-05-28 13:05:23 +02:00
2021-05-28 13:05:23 +02:00