[PATCH 1 of 8 STABLE] config: use "churn" as an example extension

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at ens-lyon.org>
# Date 1493646707 -7200
#      Mon May 01 15:51:47 2017 +0200
# Branch stable
# Node ID 57365d866c1ce3d3fa046b7f6fe44282b2158dfb
# Parent  0d892d820a51e8ea6261d788d167e54c1d9ed8de
# EXP-Topic pager
# Available At https://www.mercurial-scm.org/repo/users/marmoute/mercurial/
#              hg pull https://www.mercurial-scm.org/repo/users/marmoute/mercurial/ -r 57365d866c1c
config: use "churn" as an example extension

"Churn" is not the useful example we have, but this is the one used in
'hg help config.extensions'. As we need something to replace the deprecated
'pager' extension in the example config, we are adding 'churn'.

diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -58,6 +58,7 @@ username =
 # uncomment these lines to enable some popular extensions
 # (see 'hg help extensions' for more info)
 #
+# churn =
 # pager =""",
 
     'cloned':
@@ -105,6 +106,7 @@ default = %s
 # (see 'hg help extensions' for more info)
 #
 # blackbox =
+# churn =
 # pager =""",
 }