Report about the deprecated 'exclude' option

CCK D6's "Display fields" tabs offered the (often misunderstood, and probably ill-advertized) 'exclude' checkbox.
When checked, the field was rendered using the select formatter, but the output was left out of the $content variable in node.tpl.php, and available in $FIELD_NAME_rendered variables for manual placement in the template, e.g. in isolated in a div floated to the left of $content (= "the rest").
Original issue : #300368: Easier node templating : Let fields be excluded from $content

This method is deprecated in favor of the new render() / hide() methods in D7, and the 'exclude' setting has no equivalent. As is, those fields will be displayed regularly after migration.

We should warn about that, especially since *many* site admins just mistook the 'exclude' checkbox as an equivalent of 'hidden'.