Respond to code review feedback

 - Clarify or reword a few comments and test descriptions

 - Pluralize "annotations" correctly in the real-time update notification
   icon's tooltip

src/sidebar/components/stream-content.js

@@ -54,7 +54,8 @@ function StreamContentController(
     }
   });
 
-  // If redirected to this route from `/a/:id`, clear any existing annotations.
+  // In case this route loaded after a client-side route change (eg. from
+  // '/a/:id'), clear any existing annotations.
   store.clearAnnotations();
 
   // Perform the initial search

src/sidebar/components/stream-search-input.js

@@ -11,8 +11,7 @@ const SearchInput = require('./search-input');
 /**
  * Search input for the single annotation view and stream.
  *
- * This displays and updates the "q" query param in the URL which controls
- * the API query that is used to search for annotations.
+ * This displays and updates the "q" query param in the URL.
  */
 function StreamSearchInput({ $location, $rootScope }) {
   const [query, setQuery] = useState($location.search().q);

src/sidebar/components/test/top-bar-test.js

@@ -167,7 +167,7 @@ describe('TopBar', () => {
     assert.equal(wrapper.find(SearchInput).prop('query'), 'test-query');
   });
 
-  it('updates search in the sidebar', () => {
+  it('updates current filter when changing search query in the sidebar', () => {
     const wrapper = createTopBar();
     wrapper.find('SearchInput').prop('onSearch')('new-query');
     assert.calledWith(fakeStore.setFilterQuery, 'new-query');

src/sidebar/components/top-bar.js

@@ -90,7 +90,9 @@ function TopBar({
             <a
               className="top-bar__apply-update-btn"
               onClick={onApplyPendingUpdates}
-              title={`Show ${pendingUpdateCount} new/updated annotation(s)`}
+              title={`Show ${pendingUpdateCount} new/updated ${
+                pendingUpdateCount === 1 ? 'annotation' : 'annotations'
+              }`}
             >
               <SvgIcon className="top-bar__apply-icon" name="refresh" />
             </a>