better performance for gix blame

This really needs caching.

Author: Byron

gitoxide-core/src/repository/blame.rs

@@ -2,7 +2,9 @@ use std::{ffi::OsStr, path::PathBuf, str::Lines};
 
 use gix::bstr::BStr;
 
-pub fn blame_file(repo: gix::Repository, file: &OsStr, out: impl std::io::Write) -> anyhow::Result<()> {
+pub fn blame_file(mut repo: gix::Repository, file: &OsStr, out: impl std::io::Write) -> anyhow::Result<()> {
+    repo.object_cache_size_if_unset(repo.compute_object_cache_size_for_tree_diffs(&**repo.index_or_empty()?));
+
     let suspect = repo.head()?.peel_to_commit_in_place()?;
     let traverse: Vec<_> = gix::traverse::commit::Simple::new(Some(suspect.id), &repo.objects).collect();
     let mut resource_cache = repo.diff_resource_cache_for_tree_diff()?;