Docs: Add and correct @since docs for a variety of functions and methods.

Props keesiemeijer, chris_dev
Fixes #39343, #39357, #39344
See #39130

Built from https://develop.svn.wordpress.org/trunk@39638


git-svn-id: http://core.svn.wordpress.org/trunk@39578 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api.php

@@ -988,6 +988,8 @@ function rest_get_avatar_sizes() {
 /**
  * Validate a value based on a schema.
  *
+ * @since 4.7.0
+ *
  * @param mixed  $value The value to validate.
  * @param array  $args  Schema array to use for validation.
  * @param string $param The parameter name, used in error messages.
@@ -1110,6 +1112,8 @@ function rest_validate_value_from_schema( $value, $args, $param = '' ) {
 /**
  * Sanitize a value based on a schema.
  *
+ * @since 4.7.0
+ *
  * @param mixed $value The value to sanitize.
  * @param array $args  Schema array to use for sanitization.
  * @return true|WP_Error