wider support of backto param in mod/data

The mod/data plugin 'edit.php' page supports an optional 'backto' parameter.
It's commented as "The location to redirect back".

Currently, this parameter is only used if you click the "Cancel" button.
If you click the "Save" button, you are always redirected back to the standard database view.

Would you accept a patch that causes the 'backto' parameter to also be honoured when saving the record?
This would involve adding a new hidden field to the current form, and adding a check for the value after saving, to decide where to redirect to.