MediaWiki: switch text from red to blue in the sidebar

Change-Id: I89e4e641d0e0ea147fd9c51a88b6583873be57c2
Merge remote-tracking branch 'gerrit/6049_have_readable_buttons_and_links_with_Dawn' into HEAD

* gerrit/6049_have_readable_buttons_and_links_with_Dawn:
  MediaWiki: switch text from red to blue in the sidebar

Change-Id: I9dd5a52dfa88a954f422c39c92d952c59c954dbe
This is Tuleap 6.10.99.30

Change-Id: I0df4592f1b241b1fb254a48ea0bfa91245073fcd