Merge branch 'en/ort-perf-batch-8'

Rename detection rework continues.

* en/ort-perf-batch-8:
  diffcore-rename: compute dir_rename_guess from dir_rename_counts
  diffcore-rename: limit dir_rename_counts computation to relevant dirs
  diffcore-rename: compute dir_rename_counts in stages
  diffcore-rename: extend cleanup_dir_rename_info()
  diffcore-rename: move dir_rename_counts into dir_rename_info struct
  diffcore-rename: add function for clearing dir_rename_count
  Move computation of dir_rename_count from merge-ort to diffcore-rename
  diffcore-rename: add a mapping of destination names to their indices
  diffcore-rename: provide basic implementation of idx_possible_rename()
  diffcore-rename: use directory rename guided basename comparisons

Author: gitster

Documentation/gitdiffcore.txt

@@ -187,7 +187,7 @@ mark a file pair as a rename and stop considering other candidates for
 better matches.  At most, one comparison is done per file in this
 preliminary pass; so if there are several remaining ext.txt files
 throughout the directory hierarchy after exact rename detection, this
-preliminary step will be skipped for those files.
+preliminary step may be skipped for those files.
 
 Note.  When the "-C" option is used with `--find-copies-harder`
 option, 'git diff-{asterisk}' commands feed unmodified filepairs to