Remove aria-hidden link from tab index

More info: https://dequeuniversity.com/rules/axe/4.1/aria-hidden-focus

Author: barrymcgee

includes/header.html

@@ -6,7 +6,7 @@
   <header class="container-xl px-3 px-md-6 pt-3 pb-2 position-relative d-flex flex-justify-between width-full {% if error == '404' %} d-md-none {% endif %}">
 
     <div class="d-flex flex-items-center d-lg-none" style="z-index: 3;" id="github-logo-mobile">
-      <a href="/{{ currentLanguage }}" aria-hidden="true">
+      <a href="/{{ currentLanguage }}" aria-hidden="true" tabindex="-1">
         {% octicon "mark-github" height="32" class="text-black" %}
       </a>
       <a href="/{{ currentLanguage }}" class="h4-mktg text-gray-dark no-underline no-wrap pl-2">{% data ui.header.github_docs %}</a>

includes/sidebar.html

@@ -2,7 +2,7 @@
 <div class="sidebar d-none d-lg-block">
 
   <div class="d-flex flex-items-center p-4 position-sticky top-0 sidebar-background-color" style="z-index: 3;" id="github-logo">
-    <a href="/{{ currentLanguage }}" class="text-white" aria-hidden="true">
+    <a href="/{{ currentLanguage }}" class="text-white" aria-hidden="true" tabindex="-1">
       {% octicon "mark-github" height="32" %}
     </a>
     <a href="/{{ currentLanguage }}" class="h4-mktg text-white no-underline no-wrap pl-2 flex-auto">{% data ui.header.github_docs %}</a>