(bug 2865) Add lang attribute to firstHeading
Adds a lang attribute to <h1 id="firstHeading">.
Interface language is applied to <html> and content language is
applied to <div id="mw-content-text">. This leaves firstHeading
with the interface language, which is wrong in general. It
also causes incorrect display of the title for languages that
have custom line-height.
This patch is based on code written by Munirathnam M at
the Bangalore DevCamp (he couldn't submit it because of network
issues). It looks OK to me, but it's my first time doing anything
with $this->data in a skin, so please correct me if I'm wrong.
Change-Id: I55dd392dbf0d4f768344b66e6ceb3a023b1d5c9b