Dump constants should be in quickjs.h

[mrmbernardi]

https://github.com/quickjs-ng/quickjs/blob/482291286b9960c255ff8765d18a618cc87d89a2/quickjs.c#L81-L99

Although the comment implies its a qjs feature, the dumping is supported when quickjs is embedded anywhere. Therefore I think these should be in quickjs.h so embedders don't need to hardcode the numbers elsewhere. They should also be prefixed (perhaps with JS_ in order to avoid naming collisions.

[saghul]

Yeah makes sense. Would you like to send a PR?

[mrmbernardi]

I'll get on it soon :)