Fix issue of 'immaterial entities' in the BFO specification document

[zhengj2007]

Immaterial entity has an editor note annotation that provides some definitional information “BFO 2 Reference: Immaterial entities are divided into two subgroups:boundaries and sites, which bound, or are demarcated in relation, to material entities, and which can thus change location, shape and size and as their material hosts move or change shape or size (for example: your nasal passage; the hold of a ship; the boundary of Wales (which moves with the rotation of the Earth) [38, 7, 10” However, the typology of immaterial entities using rdfs:subClassOf also includes ‘spatial region’, so this note seems to be no longer accurate. 


We need to fix it by including "spatial region" as an immaterial entity in the BFO specification document.