perf(seo): improve accessibility and aligns with best practices (cotes2020#2289)

Author: bkayranci

_includes/topbar.html

@@ -40,7 +40,7 @@
     </nav>
     <!-- endof #breadcrumb -->
 
-    <button type="button" id="sidebar-trigger" class="btn btn-link">
+    <button type="button" id="sidebar-trigger" class="btn btn-link" aria-label="Sidebar">
       <i class="fas fa-bars fa-fw"></i>
     </button>
 
@@ -55,7 +55,7 @@
       {% endif %}
     </div>
 
-    <button type="button" id="search-trigger" class="btn btn-link">
+    <button type="button" id="search-trigger" class="btn btn-link" aria-label="Search">
       <i class="fas fa-search fa-fw"></i>
     </button>