feat(aio): improve search results functionality

* Ensure that all indexed documents are displayed in the search results.
(Previously the guide documents were not appearing because we only showed
results that had a `name` property, rather than a `name` or `title`.)
* Group the results by their containing folder (e.g. api, guide, tutorial, etc).
* Hide the results when the user hits the ESC key.
* Hide the results when the user clicks on a search result

Closes #14852

aio/transforms/angular.io-package/processors/generateKeywords.js

@@ -112,7 +112,7 @@ module.exports = function generateKeywordsProcessor(log, readFilesProcessor) {
       var searchData =
           filteredDocs.filter(function(page) { return page.searchTerms; }).map(function(page) {
             return Object.assign(
-                {path: page.path, title: page.name, type: page.docType}, page.searchTerms);
+                {path: page.path, title: page.name || page.title, type: page.docType}, page.searchTerms);
           });
 
       docs.push({