Merge branch 'nd/rebase-show-current-patch'

The new "--show-current-patch" option gives an end-user facing way to get the diff being applied when "git rebase" (and "git am") stops with a conflict. * nd/rebase-show-current-patch: rebase: introduce and use pseudo-ref REBASE_HEAD rebase: add --show-current-patch am: add --show-current-patch