improve `annot_list` readability/scanability

[jonathanj]

I don't frequently find myself needing to use annot_list, but when I do it doesn't provide much value because I can't really see what the annotations are.

I'm not sure how viable it is, but showing each entry as 2 lines (one for the file name and line number, and one for the truncated annotation) would greatly improve the experience.

The dialog itself occupies quite a small area of the screen, given that I may have hundreds of columns to spare (long lines aren't great, but very short ones aren't either.

[umputun]

merged in #195. Bumped the popup's upper width cap from 70 to 140 cols so it scales with wide terminals. Comments get ~2x the room before truncation; terminals under 80 cols are unchanged.

The 2-line layout isn't included - it halves visible-entry density which matters when there are many annotations. The width bump alone covers the core "wasted screen space" complaint.

[jonathanj]

Fantastic, thank you!