Update index.src.html

Author: caribouW3

index.src.html

@@ -820,7 +820,7 @@ <h3 id="add-report" algorithm>
      2.  <a>Queue a task</a> to [[#invoke-observers]] with a copy of |global|'s
          <a>registered reporting observer list</a>.
 
-  <h3 id="invoke-observers" algorthm>
+  <h3 id="invoke-observers" algorithm>
     Invoke reporting observers with |notify list|
   </h3>