Update WordPress to 5.2

wp-includes/cache.php

@@ -323,7 +323,7 @@ class WP_Object_Cache {
 	 * The blog prefix to prepend to keys in non-global groups.
 	 *
 	 * @since 3.5.0
-	 * @var int
+	 * @var string
 	 */
 	private $blog_prefix;
 
@@ -646,7 +646,7 @@ class WP_Object_Cache {
 	/**
 	 * Sets the data contents into the cache.
 	 *
-	 * The cache contents is grouped by the $group parameter followed by the
+	 * The cache contents are grouped by the $group parameter followed by the
 	 * $key. This allows for duplicate ids in unique groups. Therefore, naming of
 	 * the group should be used with care and should follow normal function
 	 * naming guidelines outside of core WordPress usage.