There are orphaned Snippet records in the database

[dregad]

When a user is deleted via manage_user_page.php, the plugin does not remove the user's personal Snippets, leaving orphaned data in the snippet table.

[dregad]

Need to hook the EVENT_MANAGE_USER_DELETE to remove the user's Snippets before deleting their account.

A cleanup upgrade step is also required to remove any orphan records.