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 aa1;

void main()
{
    int[int] aai;
    assert(aai is null);
    aai[0] = 52;
    assert(aai !is null);
    int i = aai[0];
    assert(i == 52);
    aai[32] = 123;
    int j = aai[32];
    assert(i == 52);
    assert(j == 123);
}