Fix search bar defocus

Author: GuillaumeGomez

src/librustdoc/html/static/main.js

@@ -1132,6 +1132,10 @@
                     e.preventDefault();
                 } else if (e.which === 16) { // shift
                     // Does nothing, it's just to avoid losing "focus" on the highlighted element.
+                } else if (e.which === 27) { // escape
+                    removeClass(actives[currentTab][0], 'highlighted');
+                    document.getElementsByClassName('search-input')[0].value = '';
+                    defocusSearchBar();
                 } else if (actives[currentTab].length > 0) {
                     removeClass(actives[currentTab][0], 'highlighted');
                 }