[PATCH 2 of 2] doc: improves merge-tools example with an overwrite of existing config

[pierre-yves.david at ens-lyon.org]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at fb.com>
# Date 1343908294 -7200
#      Thu Aug 02 13:51:34 2012 +0200
# Node ID 537e136661e8aba78973f8278002e85951f13c6c
# Parent  a3d54d20b2a5ad66a69946504ec1247ead4734b2
doc: improves merge-tools example with an overwrite of existing config

We highlight the fact that a user hgrc can overwrite the system wide
preconfiguration. As other benefit we show priority value other than 1 and shows
vimdiff configuration is usually directly available. This is valuable as vimdiff
is (surprisingly) a common request from user.

diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -819,10 +819,13 @@ Example ``~/.hgrc``::
   # Specify command line
   kdiff3.args = $base $local $other -o $output
   # Give higher priority
   kdiff3.priority = 1
 
+  # Changing the priority of preconfigured tool
+  vimdiff.priority = 0
+
   # Define new tool
   myHtmlTool.args = -m $local $other $base $output
   myHtmlTool.regkey = Software\FooSoftware\HtmlMerge
   myHtmlTool.priority = 1