rustdoc: clean up redundant search hiding results code

  * There's no need to call `history.replaceState` right before
    calling `searchState.hideResults`, which already does it.
  * There's no need to implement hiding search results when that
    is already implemented.

Author: notriddle

src/librustdoc/html/static/js/main.js

@@ -375,10 +375,7 @@ function preLoadCss(cssUrl) {
 
     function handleEscape(ev) {
         searchState.clearInputTimeout();
-        switchDisplayedElement(null);
-        if (browserSupportsHistoryApi()) {
-            history.replaceState(null, "", getNakedUrl() + window.location.hash);
-        }
+        searchState.hideResults();
         ev.preventDefault();
         searchState.defocus();
         window.hideAllModals(true); // true = reset focus for tooltips

src/librustdoc/html/static/js/search.js

@@ -2412,10 +2412,6 @@ function initSearch(rawSearchIndex) {
         const searchAfter500ms = () => {
             searchState.clearInputTimeout();
             if (searchState.input.value.length === 0) {
-                if (browserSupportsHistoryApi()) {
-                    history.replaceState(null, window.currentCrate + " - Rust",
-                        getNakedUrl() + window.location.hash);
-                }
                 searchState.hideResults();
             } else {
                 searchState.timeout = setTimeout(search, 500);