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 mini.assign1;

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

struct X
{
    int a;
    alias a b;
}
void main()
{
    X e = void;
    e.a = e.b = 5;
    printf("%d - %d\n", e.a, e.b);
    assert(e.a == 5);
    assert(e.a == e.b);
}