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 tangotests.mem3;

void main()
{
    int[] arr;
    arr ~= [1,2,3];
    assert(arr[0] == 1);
    assert(arr[1] == 2);
    assert(arr[2] == 3);
    delete arr;
    assert(arr is null);
}