Spell out duplicate hook locations.

props DrewAPicture.
fixes #25658.


git-svn-id: https://develop.svn.wordpress.org/trunk@25868 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-embed.php

@@ -215,7 +215,7 @@ class WP_Embed {
 
 			// If there was a result, return it
 			if ( $html ) {
-				//duplicate_hook
+				/** This filter is documented in wp-includes/class-wp-embed.php */
 				return apply_filters( 'embed_oembed_html', $html, $url, $attr, $post_ID );
 			}
 		}