Crash when resetting hunk of non standard size

[Zykino]

❯ gitui
Error: `hunk not found`

Command status is 1.

Steps to reproduce:

1. Make some changes in close proximity in a file
2. Open gitui, configure the "Context lines" (in the Options menu) to less than the default so it makes new, smallers hunks
3. Reset Hunk [Shift + D]
4. Back to the shell?

[extrawurst]

will be fixed in #1746