Add aria-label to search box

Authored by @stsewd

Author: jonels-msft

sphinx_rtd_theme_citus/searchbox.html

@@ -1,9 +1,22 @@
-{%- if 'singlehtml' not in builder %}
-<div role="search">
-  <form id="rtd-search-form" class="wy-form" action="{{ pathto('search') }}" method="get">
-    <input type="text" name="q" placeholder="{{ _('Search docs') }}" />
-    <input type="hidden" name="check_keywords" value="yes" />
-    <input type="hidden" name="area" value="default" />
-  </form>
+{#
+    basic/searchbox.html
+    ~~~~~~~~~~~~~~~~~~~~
+
+    Sphinx sidebar template: quick search box.
+
+    :copyright: Copyright 2007-2020 by the Sphinx team, see AUTHORS.
+    :license: BSD, see https://github.com/sphinx-doc/sphinx/blob/master/LICENSE for details.
+
+    .. note::
+
+       This file is the same, except the "Go" button was removed and the label is an aria-label.
+#}
+{%- if pagename != "search" and builder != "singlehtml" %}
+<div id="searchbox" role="search">
+  <div class="searchformwrapper">
+    <form class="search" action="{{ pathto('search') }}" method="get">
+      <input aria-label="{{ _('Search docs') }}" type="text" name="q" id="main-search" placeholder="{{ _('Search docs') }}"/>
+    </form>
+  </div>
 </div>
 {%- endif %}