Merge branch 'jc/format-patch-with-range-diff'

The inter/range-diff output has been moved to the end of the patch when format-patch adds it to a single patch, instead of writing it before the patch text, to be consistent with what is done for a cover letter for a multi-patch series. * jc/format-patch-with-range-diff: format-patch: move range/inter diff at the end of a single patch output show_log: factor out interdiff/range-diff generation