Better instructions on top of enter_bug.cgi, link to guided form

Changed instructions at the top of the bug report page to
Before reporting [% terms.abug %], please read the <a target="_blank"
href="https://www.mediawiki.org/wiki/How_to_report_a_bug">guidelines</a> and <a
href="query.cgi">search</a> for existing [% terms.bug %] reports. If you prefer
a simpler way to create a [% terms.bug %] report, try the <a
href="enter_bug.cgi?format=guided">guided bug entry form</a>.

Bug: 52696
Change-Id: I2868b211b3d6d29ed151308577f3641414697b82
Merge "Better instructions on top of enter_bug.cgi, link to guided form"