grammar : support array references in json schema (#16792)

* grammar : support array references in json schema

* Update json-schema-to-grammar.cpp

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

* grammar : improve regex when naming ref derived rules

* grammar : replace non-conformant definitions array with anyOf test case

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Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>