[PATCH 2 of 5] rebase: simplify documentation about selecting commits to rebase

[timeless]

# HG changeset patch
# User timeless <timeless at mozdev.org>
# Date 1450463081 0
#      Fri Dec 18 18:24:41 2015 +0000
# Node ID 600dd16bf6f8321d77afb1eda8b4aaf2a1e477cc
# Parent  25ec09d5ac96141e8ece7fda6b7fbf613ade966f
rebase: simplify documentation about selecting commits to rebase

diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -118,22 +118,15 @@
     destination changeset is not modified by rebasing, but new
     changesets are added as its descendants.)
 
-    You can specify which changesets to rebase in two ways: as a
-    "source" changeset or as a "base" changeset. Both are shorthand
-    for a topologically related set of changesets (the "source
-    branch"). If you specify source (``-s/--source``), rebase will
-    rebase that changeset and all of its descendants onto dest. If you
-    specify base (``-b/--base``), rebase will select ancestors of base
-    back to but not including the common ancestor with dest. Thus,
-    ``-b`` is less precise but more convenient than ``-s``: you can
-    specify any changeset in the source branch, and rebase will select
-    the whole branch. If you specify neither ``-s`` nor ``-b``, rebase
-    uses the parent of the working directory as the base.
+    There are three ways to select changesets::
 
-    For advanced usage, a third way is available through the ``--rev``
-    option. It allows you to specify an arbitrary set of changesets to
-    rebase. Descendants of revs you specify with this option are not
-    automatically included in the rebase.
+      1. Explicitly select them using ``--rev``.
+
+      2. Use ``--source`` to select a root changeset and include all of its
+      descendants.
+
+      3. Use ``--base`` to select a changeset; rebase will find ancestors
+      and their descendants which are not also ancestors of the destination.
 
     By default, rebase recreates the changesets in the source branch
     as descendants of dest and then destroys the originals. Use