Currently, TupleReturn functions will only correctly unpack values if returning an array literal. Returning a variable containing a tuple or forwarding a tuple from another TupleReturn call don't work:

/** !TupleReturn */
function foo(): [number, string]
{
    const r: [number, string] = [0, "foo"];
    return r;
}
/** !TupleReturn */
function bar(): [number, string]
{
    return foo();
}

function foo()
    local r = {0,"foo"};
    return r --Should be unpacked
end
function bar()
    return ({ foo() }) --Should not be wrapped in table
end

This PR adds handling for both of these cases.