Add some more predefined refgroups:

* `pulls` — GitHub style pull request references (`refs/pull/**`)
* `changes` — Gerrit style changeset references (`refs/changes/**`)

Author: mhagger

git-sizer.go

@@ -75,9 +75,11 @@ const Usage = `usage: git-sizer [OPTS]
  REGEXP patterns must match the full reference name.
 
  REFGROUP can be the name of a predefined reference group ('branches',
- 'tags', 'remotes', 'notes', or 'stash'), or one defined via
- gitconfig settings like the following (these can be repeated):
+ 'tags', 'remotes', 'pulls', 'changes', 'notes', or 'stash'), or one
+ defined via gitconfig settings like the following (the
+ include/exclude settings can be repeated):
 
+   * 'refgroup.REFGROUP.name=NAME'
    * 'refgroup.REFGROUP.include=PREFIX'
    * 'refgroup.REFGROUP.includeRegexp=REGEXP'
    * 'refgroup.REFGROUP.exclude=PREFIX'

internal/refopts/ref_group_builder.go

@@ -89,9 +89,17 @@ func (rgb *RefGroupBuilder) initializeStandardRefgroups() {
 	initializeGroup("branches", "Branches", git.PrefixFilter("refs/heads/"))
 	initializeGroup("tags", "Tags", git.PrefixFilter("refs/tags/"))
 	initializeGroup("remotes", "Remote-tracking refs", git.PrefixFilter("refs/remotes/"))
+	initializeGroup("pulls", "Pull request refs", git.PrefixFilter("refs/pull/"))
+
+	filter, err := git.RegexpFilter(`refs/changes/\d{2}/\d+/\d+`)
+	if err != nil {
+		panic("internal error")
+	}
+	initializeGroup("changes", "Changeset refs", filter)
+
 	initializeGroup("notes", "Git notes", git.PrefixFilter("refs/notes/"))
 
-	filter, err := git.RegexpFilter("refs/stash")
+	filter, err = git.RegexpFilter(`refs/stash`)
 	if err != nil {
 		panic("internal error")
 	}