Issue #2680307 by metzlerd, jhodgdon: Direct people to Services and Elements...

Issue #2680307 by metzlerd, jhodgdon: Direct people to Services and Elements pages on API sites in a clearer way

core/core.api.php

@@ -709,7 +709,8 @@
  * top-level core directory). Some Drupal Core modules and contributed modules
  * also define services in modulename.services.yml files. API reference sites
  * (such as https://api.drupal.org) generate lists of all existing services from
- * these files, or you can look through the individual files manually.
+ * these files. Look for the Services link in the API Navigation block.
+ * Alternatively you can look through the individual files manually.
  *
  * A typical service definition in a *.services.yml file looks like this:
  * @code

core/lib/Drupal/Core/Render/theme.api.php

@@ -324,8 +324,11 @@
  *   namespace Element, and generally extend the
  *   \Drupal\Core\Render\Element\FormElement base class.
  * See the @link plugin_api Plugin API topic @endlink for general information
- * on plugins, and look for classes with the RenderElement or FormElement
- * annotation to discover what render elements are available.
+ * on plugins. You can search for classes with the RenderElement or FormElement
+ * annotation to discover what render elements are available. API reference
+ * sites (such as https://api.drupal.org) generate lists of all existing
+ * elements from these classes. Look for the Elements link in the API Navigation
+ * block.
  *
  * Modules can define render elements by defining an element plugin.
  *