remove the default question fade

Fading was primarily motivated by wanting to prevent ugly redraw,
but we wait for both MathJax and images now.

qt/aqt/data/web/js/reviewer.ts

@@ -9,7 +9,7 @@ var ankiPlatform = "desktop";
 var typeans;
 var _updatingQueue: Promise<void> = Promise.resolve();
 
-var qFade = 50;
+var qFade = 0;
 var aFade = 0;
 
 var onUpdateHook: Array<Callback>;