Explicitly restrict exporting generic functions for entry file

[MaxGraey]

main.ts:

export function foo<T>(a: T): T {
  return a;
}

Currently generate wasm module without foo function.
Expected: should be compiler error about exporting generic functions/classes are not allowing.

[dcodeIO]

What currently happens is, if a concrete instance of it, let's say foo<i32>, is used and thus compiled somewhere in the module, it becomes exported. Not sure if that's useful or not. Restricting generic exports makes sense to me as well.

[MaxGraey]

Yeah. May be not restrict as error but print warning. Hmm...