textlinedisplaycache: short-circuit y_range invalidation
If we have a y==-1 then we are generally invalidating the whole textview. For this case, we can just discard the entire GtkTextLineDisplay cache.
Fixes #2975 (closed)
If we have a y==-1 then we are generally invalidating the whole textview. For this case, we can just discard the entire GtkTextLineDisplay cache.
Fixes #2975 (closed)