@file blocks

As reported by dman in http://drupal.org/node/212400#comment-700739, some core files are missing @file blocks. This is required for API module to read meaningful information in the file listing at http://api.drupal.org/api/files. It's also just plain a good practice, so people can tell at a glance what the file contains.

Coder should be checking for this, and raising a flag if it's not present. The format should go:

<?php
// $Id$

/**
 * @file
 * A one-line description of the file.
 *
 * Optionally, more description of the file here. Blah blah blah, describe
 * describe, describe...
 */
...