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 typeinfo6;

void main()
{
    auto ti = typeid(int[]);
    assert(ti.toString() == "int[]");
    assert(ti.next() is typeid(int));
}