Fix QuickSearch having y overflow due to KaTeX MathML being absolutely positioned at bottom

The fix is to have the parent container (i.e the searchResult class) have position:relative. Otherwise KaTeX will place a 1x1 pixel MathML element absolutely positioned below each embedded answer in the search result, which (unless constrained by a parent container having position:relative) can be even below our belowmost element -- thus leading to weird overflow.