Docs: Remove @see references for SimplePie classes.

As SimplePie is an external library, these classes are not parsed for the WordPress Code Reference, so the `@see` tags were linking to non-existing pages.

Follow-up to [38112].

Props crstauf.
Fixes #59030.

git-svn-id: https://develop.svn.wordpress.org/trunk@56379 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-feed-cache.php

@@ -19,8 +19,6 @@ _deprecated_file(
  * Core class used to implement a feed cache.
  *
  * @since 2.8.0
- *
- * @see SimplePie_Cache
  */
 #[AllowDynamicProperties]
 class WP_Feed_Cache extends SimplePie_Cache {

src/wp-includes/class-wp-simplepie-file.php

@@ -14,8 +14,6 @@
  * to hook into the process.
  *
  * @since 2.8.0
- *
- * @see SimplePie_File
  */
 #[AllowDynamicProperties]
 class WP_SimplePie_File extends SimplePie_File {

src/wp-includes/class-wp-simplepie-sanitize-kses.php

@@ -14,8 +14,6 @@
  * we cannot universally count on DOMDocument being available.
  *
  * @since 3.5.0
- *
- * @see SimplePie_Sanitize
  */
 #[AllowDynamicProperties]
 class WP_SimplePie_Sanitize_KSES extends SimplePie_Sanitize {