Don't print the entire declaration of the alliassee when `->toChars()` is called on an `AliasDeclaration`; just printing the name will do. This fixes #305, which otherwise tries to generate {{{ class E { void A() { alias /* recurse into E->toCBuffer() */ m; } } }}} by way of an infinite recursion (causing a segfault when the stack runs out).

module classes10;

class C
{
    int i;
    override char[] toString()
    {
        return "foobar";
    }
}

void main()
{
    Object o = new C;
    char[] s = o.toString();
    assert(s == "foobar");
}