[PATCH 2 of 2 STABLE] rebase: mention --rev in the help

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at ens-lyon.org>
# Date 1359671125 -3600
# Branch stable
# Node ID fadbec65d390af7e2db69ecf8850787b937718ae
# Parent  cb4cb6437ca0931d03b8b4f2caeec03983b2fc98
rebase: mention --rev in the help

The --rev option is included in the command usage but not explained anywhere.
This changeset add a small mention of it in the code to prevent confusion. This
small addition reference online help that are easier to update and improves at
release time

Following Wagner Bruna advises, this is added in a plain new paragraph to not
invalidate current translation this close from the release.

diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -86,10 +86,14 @@ def rebase(ui, repo, **opts):
     ``-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.
 
+    For advanced usages, a third way is available through the ``--rev``
+    option.  It allows to specify a strict set of changesets to rebase.
+    See online documentation for details.
+
     By default, rebase recreates the changesets in the source branch
     as descendants of dest and then destroys the originals. Use
     ``--keep`` to preserve the original source changesets. Some
     changesets in the source branch (e.g. merges from the destination
     branch) may be dropped if they no longer contribute any change.