differences between n.json-ld and n.ttl

As a continuation of #43, I compared http://rdaregistry.info/Elements/n.json-ld and http://rdaregistry.info/Elements/n.ttl.

change .json-ld to .jsonld as recommended in https://www.w3.org/TR/json-ld/#iana-considerations: File extension(s): .jsonld

ttl is missing a bunch of prefixes, add them:

@prefix owl:   <http://www.w3.org/2002/07/owl#> .
@prefix rdaa:  <http://rdaregistry.info/Elements/a/> .
@prefix rdac:  <http://rdaregistry.info/Elements/c/> .
@prefix rdae:  <http://rdaregistry.info/Elements/e/> .
@prefix rof:   <http://rdaregistry.info/Elements/rof/> .
@prefix regstat: <http://metadataregistry.org/uri/RegStatus/> .
@prefix rdai:  <http://rdaregistry.info/Elements/i/> .
@prefix rdakit: <http://metadataregistry.org/uri/profile/rdakit/> .
@prefix rdau:  <http://rdaregistry.info/Elements/u/> .
@prefix rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

ttl is missing reg:url on the namespace and each prop
jsonld has two labels differing only by lang, I think reduce to one label: rdfs:label "has related expression (nomen)"@en , "has related expression (nomen)"
ttl datatype URLs missing a slash (eg datatypeP80003), see #131
ttl has reg:hasSubClass for props, see #130
http://rdaregistry.info/Elements/n/ has rdfs:label in jsonld but dc:title in ttl: I think emit both for both
http://rdaregistry.info/Elements/n/ has skos:note in ttl but missing in jsonld: add it

one referenced concept has different info:

# jsonld
regstat:1001  rdfs:label  "Published" ;
    reg:lexicalAlias  regstat:Published.en ;
    reg:url           <http://metadataregistry.org/concept/show/id/412.html> .
# ttl
regstat:1001  a         skos:Concept ;
    skos:prefLabel  "Published"@en .

jsonld includes info for all referenced concepts, ttl has only the one above. I think there's no need to include such info

@VladimirAlexiev Thank you so much for your review(s). It's really, really helpful.

We've put off making changes to the serialization because of global versioning issues that also need to be resolved. We're also in the process of making major changes to the way the vocabularies are serialized -- right now the jsonld is built separately from the other serializations, which are all rendered from rdf/xml and this can be problematic.

Some of these, but probably not all, will be fixed in the next minor release. But this raises another issue of release versioning: We try to only version releases when we make semantic changes. Changing/correcting a single serialization is usually held until a semantic release, and then it tends to go unannounced. I've raised this as a separate issue

RDARegistry / RDA-Vocabularies

differences between n.json-ld and n.ttl #134