Avoid circular definitions

As pointed out by Soren Spile, according to _ISO 704 Terminology work — Principles and methods_ one of the rules for making definitions is that the term being defined must not be used in the definition to avoid circular definitions. In IFC4.3 there are around 20% circular definitions.

Example 1:
"IfcShadingDeviceType" – "The building element type _IfcShadingDeviceType_ defines commonly shared information for occurrences of shading devices.;"

Example 2:
"IfcStairFlight" – "A stair flight is an assembly of building components..."

Start with the issue examples and the cited ISO 704 Terminology work — Principles and methods guidance. Review the IFC4.3 definitions for terms that repeat the term being defined, documenting the affected entries and the intended wording changes. Done means the identified circular definitions have been revised without introducing new circular references.

Written by the indexing model from the issue text.