mediawiki.searchSuggest: Adjust font size for all inputs, not just magic ones

I have no idea why the fix was limited, this issue affects every single
input on every single page (including ones that are part of MediaWiki
interface itself, not skins, see If4ae687b).

Change-Id: I7a6dfbcced64dbfce5d1ab31201c98a134f72fe9