bug: side-by-side display uses too much horizontal space

[Skyppex]

Thanks for reporting a bug! Please include all of the following:

(1) A description of the issue. A screenshot is often helpful too.
The diff view has a lot of white space between making it harder to see the connecting lines.

(2) A copy of what you're diffing. If you're diffing files, include the before and after files. If you're using difftastic with a VCS repository (e.g. git), include the URL and commit hash.
Before
before-config.nu.txt

After
after-config.nu.txt

(3) The version of difftastic you're using (see difft --version) and your operating system.
Difftastic 0.61.0

Revision: 870d141 2024-10-23
Toolchain: 1.66.1
System: windows x86_64

I'm on Windows 11 Pro