Documentation: sync git.txt command list and manual page title

Also reorders a handful entries to make each list sorted
alphabetically.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 03e867a..0cb9e1f 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-git-rebase - Rebase local commits to a new head
+git-rebase - Forward-port local commits to the updated upstream head
 
 SYNOPSIS
 --------