Redmine

When a user watches an issue because of a group membership and the user does not have the `view_issue_watchers` permission, the user cannot see that she is watching the issue.

Currently the button link shows:
- "Watch" when the user is not watching the issue or watching via a group
- "Unwatch" when the user is watching the issue

It would be possible to show a third state for the button/link:
- "Watch" when the user is not watching the issue
- "Watched by group" when the user is not watching the issue but is watching the issue via a group
- "Unwatch" when the user is watching the issue

The button/link would toggle between first and third state when the user is not also watching the issue via a group, and between second and third state when the user is also watching via a group.