Use extended diagnostics in parse errors

[nlohmann]

The extended diagnostics could also help to improve the parse error exceptions. They could provide, in addition to line/column/byte count a path the last parsed value.

Example:

{
    "foo": [1, 2, flase]
}

The illegal literal flase could be easier to find when we provide a JSON Pointer /foo or even /foo/2.

For reference, this is the current exception:

[json.exception.parse_error.101] parse error at line 2, column 20: syntax error while parsing value - invalid literal; last read: '2, fl'