v0.5.1

Fixed

• parse no longer mistakes a deletion line whose content begins with --
  for a new-file header. Such a deletion renders as --- <text> in the hunk
  body; new-file detection previously triggered on any --- line while inside
  a hunk, dropping the real change and emitting a phantom file. The parser now
  tracks the old/new line counts declared by the hunk header and only treats
  --- as the next file once the current hunk body is fully consumed.
• read_limited no longer overflows limit + 1 at --max-input-bytes
18446744073709551615 (u64::MAX), which wrapped to 0 in release builds
  and silently treated any input as empty. It now uses a saturating add.
• split --at on a hunk's first context line no longer emits a leading
  context-only piece with zero net change (a hunk git apply rejects); such a
  piece is dropped.