Add *_PREVIEW_GIT_OPTS variables

[ccoVeille]

Check list

• [ ] I have performed a self-review of my code
• [X] I have commented my code in hard-to-understand areas
• [X] I have made corresponding changes to the documentation

Description

These variables can be used to tune the rendering of the previews

The following example allows listing the content of the stash before opening it.

FORGIT_STASH_SHOW_PREVIEW_GIT_OPTS="--patch-with-stat --stat-count=10"

Type of change

• [ ] Bug fix
• [X] New feature
• [ ] Refactor
• [ ] Breaking change
• [X] Documentation change

Test environment

• Shell
  • [ ] bash
  • [ ] zsh
  • [ ] fish
• OS
  • [X] Linux
  • [ ] Mac OS X
  • [ ] Windows
  • [ ] Others:

Fixes #391

[ccoVeille]

This is a WIP code change, I made the changes, but I didn't test them all now.

You can still review it now, as the review will be mostly about variables naming and documentation I think

So please review

[ccoVeille]

maybe @carlfriedrich @sandr01d ?

[sandr01d]

I will give you a review, but I'm currently very busy and won't make it today. I'll try to find the time tomorrow.

[ccoVeille]

No rush. I was busy for months. This PR can wait weeks, no worries

[ccoVeille]

I'm in holidays, without computer and with limited and sporadic internet connection.

I'll give be back in about a week, and will then take a look at your feedbacks

[ccoVeille]

I'm still busy, I'll be back to normal in the next weeks.

[ccoVeille]

While this PR was interesting at first. It led me to a refactoring that is way bigger than I initially planned. A refactoring I wasn't 100% confident about when I started working on it 9 months ago.

Since then, the code has diverged, new features were added… it won't be easy.

I'm pretty confident I won't come back to this PR, so I'm closing it.

I'm not even sure if the feature I was looking for hasn't been implemented since I worked on it.

Thanks to anyone who took a look at my PR.

For records, everything started from this small PR

• https://github.com/wfxr/forgit/pull/389