Merge branch 'pb/diff-doc-raw-format' into maint

Update "git diff/log --raw" format documentation.
source: <redacted>

* pb/diff-doc-raw-format:
  diff-index.txt: update raw output format in examples
  diff-format.txt: correct misleading wording
  diff-format.txt: dst can be 0* SHA-1 when path is deleted, too