Docs: For clarity, add some information about the return types of get_option().

Props ReneHermi, johannadevos

See #51278


git-svn-id: https://develop.svn.wordpress.org/trunk@49600 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/option.php

@@ -25,7 +25,8 @@
  *
  * @param string $option  Name of the option to retrieve. Expected to not be SQL-escaped.
  * @param mixed  $default Optional. Default value to return if the option does not exist.
- * @return mixed Value set for the option.
+ * @return mixed Value set for the option. A value of any type may be returned, including
+ *               array, boolean, float, integer, null, object, and string.
  */
 function get_option( $option, $default = false ) {
 	global $wpdb;