ttl problems

[VladimirAlexiev]

@ellismarkf We noticed the following problems with the turtle (ttl) highlighter, and by inclusion the sparql highlighter. The turtle grammar is at https://www.w3.org/TR/turtle/#terminals

1. pnames are highlighted only up to the first :
2. Not all PN_CHARS are allowed, eg ff-map:is highlighted only *after* the-. One should be especially careful that .` is allowed in PNAMES but only if followed by another allowed char (see PN_PREFIX, PN_LOCAL)
3. triple-apostrophe and triple-quote strings are mixed up. Eg this

'''foo """and""" bar'''

is highlighted as two strings: '''foo """ and """ bar'''
4. blank nodes are not highlighted
5. Would be nice to highlight @lang and ^^dt as a distinct class ("type")

We'll try to fix these problems

cc @nikolatulechki

[VladimirAlexiev]

Implemented in #1746. cc @ellismarkf

Also added highlighting for JSON embedded in SPARQL triple-quote literal, which is used in Ontotext Elasticsearch and SOLR connectors. See example in https://github.com/VladimirAlexiev/highlight.js/blob/feature/language-sparql-ttl/test/detect/sparql/default.txt#L31