Docs: Improve description for `wp_unique_filename()`.

Props stevenlinx.
Fixes #50762.
Built from https://develop.svn.wordpress.org/trunk@48606


git-svn-id: http://core.svn.wordpress.org/trunk@48368 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -2449,11 +2449,12 @@ function _wp_upload_dir( $time = null ) {
  * Get a filename that is sanitized and unique for the given directory.
  *
  * If the filename is not unique, then a number will be added to the filename
- * before the extension, and will continue adding numbers until the filename is
- * unique.
+ * before the extension, and will continue adding numbers until the filename
+ * is unique.
  *
- * The callback is passed three parameters, the first one is the directory, the
- * second is the filename, and the third is the extension.
+ * The callback function allows the caller to use their own method to create
+ * unique file names. If defined, the callback should take three arguments:
+ * - directory, base filename, and extension - and return a unique filename.
  *
  * @since 2.5.0
  *

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-beta3-48605';
+$wp_version = '5.5-beta3-48606';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.