rc diff: skip email quotes in diff-jump

When reading and writing emails that contain patches (possibly
email-quoted), it can be convenient to the jump to the source file.
Allow this by making diff-jump (bound to <ret> in git-diff
buffers) ignore leading email quotes ("> "). A line that starts with
"> " should not occur in a unified diff, so this won't affect other
use cases.

Observe that diff-jump even works around interleaved replies; they
will not affect the computed line numbers because we ignore lines
that don't match ^(> )*[ +-].

0 files changed, 0 insertions, 0 deletions