Merge branch 'nd/diff-stat-with-summary'

"git diff" and friends learned "--compact-summary" that shows the information usually given with the "--summary" option on the same line as the diffstat output of the "--stat" option (which saves vertical space and keeps info on a single path at the same place). * nd/diff-stat-with-summary: diff: add --compact-summary diff.c: refactor pprint_rename() to use strbuf