Merge branch 'kn/for-each-branch'

Update "git branch" that list existing branches, using the
ref-filter API that is shared with "git tag" and "git
for-each-ref".

* kn/for-each-branch:
  branch: add '--points-at' option
  branch.c: use 'ref-filter' APIs
  branch.c: use 'ref-filter' data structures
  branch: drop non-commit error reporting
  branch: move 'current' check down to the presentation layer
  branch: roll show_detached HEAD into regular ref_list
  branch: bump get_head_description() to the top
  branch: refactor width computation

Documentation/git-branch.txt

@@ -11,7 +11,8 @@ SYNOPSIS
 'git branch' [--color[=<when>] | --no-color] [-r | -a]
 	[--list] [-v [--abbrev=<length> | --no-abbrev]]
 	[--column[=<options>] | --no-column]
-	[(--merged | --no-merged | --contains) [<commit>]] [<pattern>...]
+	[(--merged | --no-merged | --contains) [<commit>]] [--sort=<key>]
+	[--points-at <object>] [<pattern>...]
 'git branch' [--set-upstream | --track | --no-track] [-l] [-f] <branchname> [<start-point>]
 'git branch' (--set-upstream-to=<upstream> | -u <upstream>) [<branchname>]
 'git branch' --unset-upstream [<branchname>]
@@ -231,6 +232,19 @@ start-point is either a local or remote-tracking branch.
 	The new name for an existing branch. The same restrictions as for
 	<branchname> apply.
 
+--sort=<key>::
+	Sort based on the key given. Prefix `-` to sort in descending
+	order of the value. You may use the --sort=<key> option
+	multiple times, in which case the last key becomes the primary
+	key. The keys supported are the same as those in `git
+	for-each-ref`. Sort order defaults to sorting based on the
+	full refname (including `refs/...` prefix). This lists
+	detached HEAD (if present) first, then local branches and
+	finally remote-tracking branches.
+
+
+--points-at <object>::
+	Only list branches of the given object.
 
 Examples
 --------