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 classes5;
extern(C) int printf(char*, ...);

struct S
{
    long l;
}

class C
{
    C c;
    S s;
}

void main()
{
    C c = new C;
    long* lp = void;
    {c.s.l = 64;}
    {assert(c.s.l == 64);}
    {lp = &c.s.l;}
    {assert(*lp == 64);}
    printf("classes5 success\n");
}