Suggestion: add ability to split hunks into smaller hunks

[OliverJAsh]

Is your feature request related to a problem? Please describe.
I like the ability to select hunks, but sometimes the hunks are too big and need to be broken down into smaller hunks. git add --patch provides an option for this—the s shortcut. It would be great if lazygit could provide something similar.

Describe the solution you'd like
When a hunk is selected, pressing s should split it into smaller hunks, like how it works in git add --patch.

Describe alternatives you've considered

Additional context

[jesseduffield]

currently if you hit enter on a file you'll enter line-by-line staging mode where you can stage the file on a per-line basis. In that context, space will stage a line and v allows you to select a range of lines to stage. As for splitting up hunks, I'm not quite sure how I'd go about that. I think the line-by-line approach is pretty solid. What are your thoughts?

[OliverJAsh]

Here's an example. Say I have these unstaged changes:

I only want to stage the first set of changes. Unfortunately Git considers all of the changes as a single hunk, because these changes live so close together. That's where s comes in useful.

I could use the line-by-line approach, but that would be annoying if there were many lines in the change. The change could be hundreds of lines long 🤔

[alok]

I'm also in favor of this, as it makes feasible mass editing a bunch of changes in a single pass, then going back and committing them separately. Line by line is not convenient there.

[alok]

@jesseduffield thoughts on this?

[jesseduffield]

I'm in favour of it, but last time I checked it wasn't straightforward to do. Happy to give pointers if somebody wants to tackle it

[Xevion]

Beginner; unfortunately when I press a to select the hunk, it selects the entire file. There are very clear areas of separation between the hunk, yet it selects the entire file. Forced to use v to select my commit somewhat slowly.