Make blame.ignoreRevsFile .git-blame-ignore-revs the default #1494

Some projects to have a .git-blame-ignore-revs file to ignore e.g. coding style reformatting commits. GitHub uses that file by default: https://docs.github.com/en/repositories/working-with-files/using-files/viewing-a-file#ignore-commits-in-the-blame-view.

Alternatively, it would be nice to ignore error if the file does not exist, that way we can set the config globally without breaking every repo that does not have the file: git config --global blame.ignoreRevsFile .git-blame-ignore-revs.