Reference external url in link to markdown syntax guide

app/views/notifications/_form.html.erb

@@ -22,7 +22,7 @@
       <%= f.govuk_check_box :show_on_unauthenticated_pages, 1, 0, multiple: false, label: { text: "Show this notification on unauthenticated pages, for example the start page" } %>
     <% end %>
 
-    <span class="govuk-caption-m govuk-!-margin-bottom-6">View <%= govuk_link_to "markdown syntax guide", "https://www.markdownguide.org/basic-syntax/" %></span>
+    <span class="govuk-caption-m govuk-!-margin-bottom-6">View <%= govuk_link_to "markdown syntax guide at markdownguide.org", "https://www.markdownguide.org/basic-syntax/" %></span>
 
     <%= f.govuk_submit "Continue" %>
   </div>