Improve performance for large repos

[carlthome]

Noticed in nixpkgs that how git is called on each line leads to heavy CPU usage on a MacBook M1 Air. Should fix that.

[carlthome]

--until 1.day

might be helpful but need to double-check that it behaves as intended.

[mishraprafful]

Another apporach could be to do a git blame and when a file is opened by the user, and then store it on memory, and just fetch the blame from this file when the cursor is on a line, this might make the IO less, but memory usage more.

But I think this is worth considering and trying out.