After pressing the "Update" button, the WordPress.com Text editor mangles this: 

    <code>IEnumerable<IGrouping<FruitVariety, Fruit>></code>

into this:

    <code>IEnumerable&lt;IGrouping&gt;</code>

it should mangle it into this:

    <code>IEnumerable&lt;IGrouping&lt;FruitVariety, Fruit&gt;&gt;</code>