Merge branch 'mg/diff-stat-count'

Merge branch 'mg/diff-stat-count'

* mg/diff-stat-count:
  diff --stat-count: finishing touches
  diff-options.txt: describe --stat-{width,name-width,count}
  diff: introduce --stat-lines to limit the stat lines
  diff.c: omit hidden entries from namelen calculation with --stat