Merge branch 'ew/diff'

Merge branch 'ew/diff'

* ew/diff:
  templates/hooks--update: replace diffstat calls with git diff --stat
  diff: do not use configuration magic at the core-level
  Update diff-options and config documentation.
  diff.c: --no-color to defeat diff.color configuration.
  diff.c: respect diff.renames config option