Wrap lines config option

[jonathanj]

I like the layout change to the commits view, but I found myself being frustrated by line wrapping consuming a lot of space when I use gitu in a split on my laptop:

I had Claude add a general.wrap_lines option (defaulting to true, preserving the current behaviour) and reviewed its implementation which seems reasonable to me (packing spans).

This is what it looks like with general.wrap_lines = false:

(Let me know if i should squash the commits together.)

Checklist

• The modified code has some test-coverage (where applicable).
• New unreleased features/fixes/styling and performance improvements are documented via git: feat: / fix: / style: / perf:. Or e.g. perf(highlighting):.
  See https://github.com/altsem/gitu/blob/master/docs/dev-tooling.md

[altsem]

Nice! Should we keep the ellipsis at the end for truncated lines?