Coding Standards: Move wp-includes/class-oembed.php to wp-includes/class-wp-oembed.php.

This renames the file containing the `WP_oEmbed` class to conform to the coding standards.

This commit also includes:

- A new `class-oembed.php` that includes the new file, for anyone that may've been including the file directly.
- Replaces references to the old filename with the new filename.

See #47632.



git-svn-id: https://develop.svn.wordpress.org/trunk@45663 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-oembed-controller.php

@@ -194,7 +194,7 @@ final class WP_oEmbed_Controller {
 			return new WP_Error( 'oembed_invalid_url', get_status_header_desc( 404 ), array( 'status' => 404 ) );
 		}
 
-		/** This filter is documented in wp-includes/class-oembed.php */
+		/** This filter is documented in wp-includes/class-wp-oembed.php */
 		$data->html = apply_filters( 'oembed_result', _wp_oembed_get_object()->data2html( (object) $data, $url ), $url, $args );
 
 		/**