Allow metadata to be updated via wp_update_comment().

Passing an array of `comment_meta` into `wp_update_comment()` will
now update corresponding metadata. Similar functionality already
exists in `wp_insert_comment()`.

Props dshanske, kraftbj.
Fixes #36784.

git-svn-id: https://develop.svn.wordpress.org/trunk@40981 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/comment.php

@@ -52,6 +52,21 @@ class Tests_Comment extends WP_UnitTestCase {
 		$this->assertEquals( 'pingback', $comment->comment_type );
 	}
 
+	/**
+	 * @ticket 36784
+	 */
+	function test_wp_update_comment_updates_comment_meta() {
+		$comment_id = self::factory()->comment->create( array( 'comment_post_ID' => self::$post_id ) );
+		wp_update_comment( array(
+			'comment_ID' => $comment_id,
+			'comment_meta' => array(
+				'food' => 'taco',
+				'sauce' => 'fire',
+			),
+		) );
+		$this->assertEquals( 'fire', get_comment_meta( $comment_id, 'sauce', true ) );
+	}
+
 	/**
 	 * @ticket 30307
 	 */