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 typeinfo4;

void main()
{
    auto ti = typeid(void*);
    assert(ti.toString() == "void*");
    assert(ti.tsize() == size_t.sizeof);
    void* a = null;
    void* b = a + 1;
    assert(ti.compare(&a,&b) < 0);
}