message: docs: fix incorrect header on custom event docs
  PR Close
diff: @@ -1027,7 +1027,7 @@ Although the `ItemDetailComponent` has a delete button, it doesn't know how to d
  Here are the pertinent excerpts from that `ItemDetailComponent`:
  -<code-example path="event-binding/src/app/item-detail/item-detail.component.html" linenums="false" header="src/app/item-detail/item-detail.component.ts (template)" region="line-through">
  +<code-example path="event-binding/src/app/item-detail/item-detail.component.html" linenums="false" header="src/app/item-detail/item-detail.component.html (template)" region="line-through">
  </code-example>
  <code-example path="event-binding/src/app/item-detail/item-detail.component.ts" linenums="false" header="src/app/item-detail/item-detail.component.ts (deleteRequest)" region="deleteRequest">
  