fix: - fix missing style (DocSearch-VisuallyHiddenForAccessibility) for search bar

Author: Gary Zhang

src/styles/docsearch.css

@@ -52,7 +52,9 @@
 .DocSearch--active {
   overflow: hidden !important;
 }
-
+.DocSearch-VisuallyHiddenForAccessibility{
+  visibility: hidden;
+}
 .DocSearch-Container {
   position: fixed;
   z-index: 200;