Merge branch 'pk/bisect-use-show'

When "git bisect" reports the commit it determined to be the
culprit, we used to show it in a format that does not honor common
UI tweaks, like log.date and log.decorate.  The code has been
taught to use "git show" to follow more customizations.

* pk/bisect-use-show:
  bisect: report the found commit with "show"