Remove dead IE code

h/static/scripts/annotator/main.js

@@ -44,15 +44,6 @@ if (window.PDFViewerApplication) {
   options['Document'] = {};
 }
 
-// Simple IE autodetect function
-// See for example https://stackoverflow.com/questions/19999388/jquery-check-if-user-is-using-ie/21712356#21712356
-var ua = window.navigator.userAgent;
-if ((ua.indexOf("MSIE ") > 0) ||     // for IE <=10
-    (ua.indexOf('Trident/') > 0) ||  // for IE 11
-    (ua.indexOf('Edge/') > 0)) {     // for IE 12
-  options["DomTextMapper"] = {"skip": true}
-}
-
 if (window.hasOwnProperty('hypothesisConfig')) {
   if (typeof window.hypothesisConfig === 'function') {
     options = jQuery.extend(options, window.hypothesisConfig());