Fix regex when json values includes quotes

[erikn69]

There is a bug when you has '" "', or when you try to save json values on db
Examples:

SELECT '{"json_index":"json_value"}' AS test;
SELECT '"json_string"' AS test;
SELECT "'string_value'" AS test;
SELECT '`string_value`' AS test;

Result:

Result with this PR:

---

There is also another bug

SELECT '\'string_value' AS test;

Maybe solution

{
    name: 'string',
    regex: /(['].*?(?<!\\)[']|["].*?(?<!\\)["]|[`].*?(?<!\\)[`])/g
}

[scriptcoded]

Thank you for the PR! The linter seems to complain about the test you added (https://github.com/scriptcoded/sql-highlight/pull/40/files#diff-5bb8db779819ddef5956a5d9d5949c05ef7445237656ca37bf2f02720271440bR21). If you can fix that issue I'd be happy.

As for the other bug you mentioned, it's something I'm aware. Some language features are hard to capture using only regular expressions, and I have briefly thought about rewriting this library using something like Ohm for parsing. However, based on this change I think we should be able to add support for escaping quotes. It's not pretty, but I think it'll do the job:

(['](?:\\'|.)*?[']|["](?:\\"|.)*?["]|[`](?:\\`|.)*?[`])

https://regex101.com/r/eKffvh/1

[erikn69]

Done