[db2html-css.xsl] Bold userinput inside programlisting
[db2html-css.xsl] Bold userinput inside programlisting

Ubuntu wants userinput bolded, which we already do inside
screen.  But they use programlisting instead of screen.
I don't know why, but it's a safe change.

Distrotech/yelp-xsl,Distrotech/yelp-xsl