Cache API, Docs: Remove private delegation from cache priming functions.

Remove the private delegation from the following cache priming functions for various object types:

- `_prime_post_caches()`
- `_prime_term_caches()`
- `_prime_comment_caches()`
- `_prime_network_caches()`
- `_prime_site_caches()`
- `_get_non_cached_ids() `

Plugins and themes are now encouraged to use these functions to improve the performance of their code by reducing the number of database queries.

Props robinwpdeveloper, desrosj, SergeyBiryukov, mukesh27, costdev.
Fixes #56386.



git-svn-id: https://develop.svn.wordpress.org/trunk@53944 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/functions.php

@@ -6988,7 +6988,7 @@ function wp_debug_backtrace_summary( $ignore_class = null, $skip_frames = 0, $pr
  * Retrieves IDs that are not already present in the cache.
  *
  * @since 3.4.0
- * @access private
+ * @since 6.1.0 This function is no longer marked as "private".
  *
  * @param int[]  $object_ids Array of IDs.
  * @param string $cache_key  The cache bucket to check against.