[XForms] Suggestion for docu

[TG]

Hello,

A small clarification may be helpfull for new users.

Chapter 32.4 Object Attributes

fl_move_object() can be used on an object group, because every object in 
this group can be set relative to its position.

Moving all group members to a single position is not usefull, so you 
shall use fl_set_object_position() only for a single object.

Regard
Thomas