the advanced form, a.k.a. power search box.
&$showSections: an array to add values with more options to
$term: the search term (not a title object)
-$opts: an array of hidden options (containing 'redirs' and 'profile')
+&$opts: an array of hidden options (containing 'redirs' and 'profile')
'SpecialSearchProfileForm': Allows modification of search profile forms.
$search: special page object