Pick up identifier name

[hmil]

Enhance error messages by using the actual name of the checked symbol instead of just $ when possible.

Example:

@ValidateClass()
class MyClass {
    myMethod(@AssertType() make, @AssertType() model) { }
}

Before: validation failed at $: expected 'type' in object (Can't tell which parameter failed)
After: validation failed at model: expected 'type' in object (More useful)

---

This code is just a quick and dirty PoC. I can clean it up if you are open to this enhancement.

[woutervh-]

Hi @hmil ,

Thank you for your contribution. I think it's a great idea!

I'm happy to merge this PR. You mentioned you can clean it up. Let me know when you are finished with that, and then I will merge this :)

[hmil]

It's all good on my side 👌

[woutervh-]

Awesome, thanks!

[woutervh-]

Released as v0.15.0 https://github.com/woutervh-/typescript-is/releases/tag/v0.15.0