message: add links to how to guides from customizing search
diff: @@ -279,6 +279,8 @@ an example:
  </SearchResult>
  ```
  +> For more advanced customization of the Search frontend, also see how to guides such as [How to implement your own Search API](./how-to-guides.md#how-to-implement-your-own-search-api) and [How to customize search results highlighting styling](./how-to-guides.md#how-to-customize-search-results-highlighting-styling)
  +
  ### Backend
  Backstage Search isn't a search engine itself, rather, it provides an interface
  @@ -380,3 +382,5 @@ indexBuilder.addCollator({
  }),
  });
  ```
  +
  +> For more advanced customization of the Search backend, also see how to guides such as [How to index TechDocs documents](./how-to-guides.md#how-to-index-techdocs-documents) and [How to limit what can be searched in the Software Catalog](./how-to-guides.md#how-to-limit-what-can-be-searched-in-the-software-catalog)
  