[PATCH STABLE] doc: fix underline length for config title (issue5949)

[Boris Feld]

# HG changeset patch
# User Boris Feld <boris.feld at octobus.net>
# Date 1533027314 -7200
#      Tue Jul 31 10:55:14 2018 +0200
# Branch stable
# Node ID ddaf3b3083312547e84ee3b4b95c76573e5baa28
# Parent  e06a10d3b926844b5a933ec2b8f2b70cf1fb941e
# EXP-Topic doc-fix
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r ddaf3b308331
doc: fix underline length for config title (issue5949)

This was an error in the initial commit.

Thanks go to Marcel Svitalský for reporting the bug.

diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -1774,7 +1774,7 @@ have a definite end point.
 Alias definitions for revsets. See :hg:`help revsets` for details.
 
 ``storage``
-----------
+-----------
 
 Control the strategy Mercurial uses internally to store history. Options in this
 category impact performance and repository size.