Attribute/property/enum descriptions shouldn't have line-breaks

I found some descriptions containing random `\n` in them, should probably remove all of them:
> 'Allows for specification of user defined roles beyond the\nenumeration values provided by Role attribute of type IfcRoleEnum.\nWhen a value is provided for attribute UserDefinedRole in parallel\nthe attribute Role shall have enumeration value USERDEFINED.'

The issue names no file, test, or entry point. Start by locating the source data for IFC attribute, property, and enum descriptions, then search it for embedded line breaks like the quoted example. Done means the affected descriptions no longer contain unintended line breaks while their wording remains unchanged.

Written by the indexing model from the issue text.