Add a function that outputs the exact type

[jandockx]

During debugging the d.ts files, it is often helpful to see the type TS inferred.

Now, I do this by writing temporarily

expectType<string>(expressionOfAComplexType)

This fails, and in the error message we see the type TS inferred, e.g.:

Argument of type { <T>(this: T, thisArg: any): T; <A0, A extends any[], R>(this: new (arg0: A0, ...args: A) => R, thisArg: any, arg0: A0): new (...args: A) => R; <A0, A1, A extends any[], R>(this: new (arg0: A0, arg1: A1, ...args: A) => R, thisArg: any, arg0: A0, arg1: A1): new (...args: A) => R; <A0, A1, A2, A extends any[], R>(thi... is not assignable to parameter of type string.

That helps for "not to complex" types. But, as you can see, when the type becomes more complex, the output is shortened with ellipsis.

It would be nice to have a printType that we could use like

printType(expressionOfAComplexType)

that would print the complete type to stdout.

[BendingBender]

@jandockx @sindresorhus @papb Would you mind testing my PR whether it is helpful for your use case or whether something is missing?