[PATCH website] downloads: replace yum with dnf for fedora instructions

[David Demelier]

# HG changeset patch
# User David Demelier <markand at malikania.fr>
# Date 1499062737 -7200
#      Mon Jul 03 08:18:57 2017 +0200
# Node ID 6f3cfd6dcc28ac0d2aa35f19e48fe221293f16b7
# Parent  4b88b3c4fc807a3d1e9a98b670e2f710796e73c1
downloads: replace yum with dnf for fedora instructions

diff -r 4b88b3c4fc80 -r 6f3cfd6dcc28 templates/downloads/index.html
--- a/templates/downloads/index.html	Sun May 14 21:47:27 2017 -0500
+++ b/templates/downloads/index.html	Mon Jul 03 08:18:57 2017 +0200
@@ -124,7 +124,7 @@
 $ apt-get install mercurial
 
 # Fedora
-$ yum install mercurial
+$ dnf install mercurial
 
 # Gentoo
 $ emerge mercurial