[PATCH] update: clarify that update changes the parent revison

[Adrian Buehlmann]

# HG changeset patch
# User Adrian Buehlmann <adrian at cadifra.com>
# Date 1308905465 -7200
# Branch stable
# Node ID 20039337fd0ce4d22cf1f3718b7c38f0347e4070
# Parent  d1788426c24da3851005a5606fef16fed64654e7
update: clarify that update changes the parent revison

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -5051,6 +5051,9 @@
     found, the working directory is updated to the specified
     changeset.
 
+    Update sets the working directory's parent revison to the specified
+    changeset (see :hg:`help parents`).
+
     The following rules apply when the working directory contains
     uncommitted changes: