Fix a typo in missing_exact_template.html.erb

Author: byroot

actionpack/lib/action_dispatch/middleware/templates/rescues/missing_exact_template.html.erb

@@ -11,7 +11,7 @@
     </p>
     <p>
       For example, a <code>BooksController#index</code> action defined in <code>app/controller/books_controller.rb</code> should have a corresponding view template 
-      in a file named <code>app/views/books/index.erb.html</code>.
+      in a file named <code>app/views/books/index.html.erb</code>.
     </p>
     <p>
       However, if this controller is an API endpoint responding with 204 (No Content), which does not require a view template because it doesn't serve an HTML response, then this error will occur when trying to access it with a browser. In this particular scenario, you can ignore this error.