Only keep one blame up-to-date (#11274)

I was experiencing hang, and we blamed it on spawning a few hundred git
processes
simultaneously.

cc @MrNugget

Release Notes:

- Fixed slowness with hundreds of buffers open doing git blame.
3b5fd4ea66Conrad Irwin committed on 5/1/2024, 10:25:26 PM· committed by GitHubparenteb0f1e7
2 files changedLine totals unavailable