[PATCH 2 of 3] help: modify template help to use a comma instead of newline for extras

[Matthew Turk]

# HG changeset patch
# User Matthew Turk <matthewturk at gmail.com>
# Date 1385066846 18000
#      Thu Nov 21 15:47:26 2013 -0500
# Node ID 547837e59d439af3c907931ca65cab911d00dfe3
# Parent  e4c89fff1cc57f532d43d0015445ab44a739f6d7
help: modify template help to use a comma instead of newline for extras.

Newlines need different escaping, and this is a more terse example of extras in
template help.

diff -r e4c89fff1cc5 -r 547837e59d43 mercurial/help/templates.txt
--- a/mercurial/help/templates.txt	Thu Nov 21 15:46:49 2013 -0500
+++ b/mercurial/help/templates.txt	Thu Nov 21 15:47:26 2013 -0500
@@ -105,4 +105,4 @@
 
 - Display the contents of the 'extra' field, one per line::
 
-  $ hg log -r 0 --template "{join(extras, '\n')}\n"
+  $ hg log -r 0 --template "{join(extras, ', ')}\n"