"Mark as read?" confirmation dialogs should acknowledge muted messages

[chrisbobbe]

For our initial solution to

• Get confirmation before marking an interleaved feed as unread #1858

we'll show a confirmation dialog with text like "26 messages will be marked as read." If the view contains muted messages, they won't appear in the message list, and the count in that dialog won't include them. However, on tapping the confirm button, they will be marked as read, just like the visible, unmuted messages.

We should change the message to say something like the following (cc @alya 🙂) depending on whether there are muted and/or unmuted unreads:

• When none are muted: "26 messages will be marked as read."
• When some are muted: "10026 messages will be marked as read, including 10000 muted messages." (A high number like that would be common for me in the combined feed.)

Implementation

The Unreads model will need to offer unread counts that include all unreads in a given narrow, including muted unreads.

Related issues

• "Mark as read?" confirmation dialogs should acknowledge uncertainty when there are very many unreads #2031