Merge branch 'mg/status-v-v'

"git status" now allows the "-v" to be given twice to show the
differences that are left in the working tree not to be committed.

* mg/status-v-v:
  commit/status: show the index-worktree diff with -v -v
  t7508: test git status -v
  t7508: .gitignore 'expect' and 'output' files

Documentation/git-commit.txt

@@ -284,6 +284,10 @@ configuration variable documented in linkgit:git-config[1].
 	would be committed at the bottom of the commit message
 	template.  Note that this diff output doesn't have its
 	lines prefixed with '#'.
++
+If specified twice, show in addition the unified diff between
+what would be committed and the worktree files, i.e. the unstaged
+changes to tracked files.
 
 -q::
 --quiet::