fix regression in parseIfStatement

[ghost]

In #106 I broke

 if (TypeCtor(Type) ident = stuff){}

by allowing

 if (TypeCtor ident = stuff){}

It's well tested now.

[Hackerpilot]

I should have tested this more before tagging another beta. This change breaks this code:

void main()
{
	if ((a && b) || c)
	{
	}
}

[ghost]

It must be

            if (currentIs(tok!"("))
                index--;

that must not be called if not typector is consumed.

[ghost]

Indeed:

            // consume for TypeCtors = identifier
            if (isTypeCtor(current.type))
            {
                while (isTypeCtor(current.type))
                {
                    const prev = current.type;
                    advance();
                    if (current.type == prev)
                        warn("redundant type constructor");
                }
                // goes back for TypeCtor(Type) = identifier
                if (currentIs(tok!"("))
                    index--;
            }

works for all.