vim-gitgutter is buggy. vim-signify might be better, it does allow configuration of which events trigger a sign column update and this patch takes advantage of that. Firstly, the `CursorHold` and `CursorHoldI` events are disabled and replaced with `InsertLeave` and `TextChanged` events. This makes the sign column updates immediate, and since vim-signify is asynchronous it's faster too.