Merge branch 'maint'

* maint:
  Change double quotes to single quotes in message
  Documentation: clarify .gitattributes search
  git-checkout.txt: clarify that <branch> applies when no path is given.
  git-checkout.txt: fix incorrect statement about HEAD and index

Conflicts:
	Documentation/git-checkout.txt

diff --cc Documentation/git-checkout.txt
Simple merge

diff --cc builtin-checkout.c
Simple merge