Improve defintion of prof:isTransitiveProfileOf

[rob-metalinkage]

Proposal from @kcoyle in w3c/dxwg#1061

I suggest "The transitive closure of the prof:isProfileOf property. Relates a profile to another specification that it is a profile of, possibly via a chain of intermediate profiles that are in prof:isProfileOf relationships".

I also suggest to amend the existing usage note, relinquishing it from too strong wording on conformance, into "This is a convenience property that may be used to access all specifications (including other profiles) that could provide useful information and related resources for the Profile (for example, for better identifying conformance requirements). This avoids forcing clients to traverse a profile hierarchy to find all relevant resources. If this property is used, then all such relationships should be present so a client can safely avoid hierarchy traversal."

[kcoyle]

@rob-metalinkage That's @aisaac 's proposal. I haven't ventured into that particular property's definition yet. Also, why is this a separate issue? I thought we were covering the definitions with w3c/dxwg#1061