JSON grammar fix: json can be any value
JSON grammar fix: json can be any value

The ECMA-404 standard says

> A JSON text is a sequence of tokens formed from Unicode code points
> that conforms to the JSON value grammar.

http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf

This corrects the JSON grammar so that it conforms to the spec, and will correctly parse any legal JSON value, instead of only objects and arrays.
antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4