Focus search input immediately after keyboard shortcut

We were previously waiting for the `openSidebar()` promise to resolve,
which resulted in lost keyboard input if you immediately started typing
after pressing / or s.

Author: zachallaun

assets/js/keyboard-shortcuts.js

@@ -83,9 +83,7 @@ function handleKeyUp (event) {
 function searchKeyAction (event) {
   closeModal()
   openSidebar()
-    .then(() => {
-      focusSearchInput()
-    })
+  focusSearchInput()
 }
 
 function toggleHelpModal () {