Allow void ternary expressions

[dcodeIO]

Fixes #1960 by special-casing compilation of ternary ifs where contextual type is void, dropping each arm evaluating to a concrete value, including ignoring type mismatch if not relevant.

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[MaxGraey]

could you also add this test?

function boo(): void {}
function foo(fn: () => void): void {
  fn();
}
foo(() => boo()); // allow return void

[dcodeIO]

Seems like a separate issue that is rather related to return. Does the code snippet work right now?

[MaxGraey]

Does the code snippet work right now?

no Currently it broke compiler

[dcodeIO]

Wasn't there an issue somewhere about that, hmm...

[MaxGraey]

not sure but I can create

[dcodeIO]

I think there was, but can't find it rn. And yeah, a new one seems good :)