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.aa2_1;

int main()
{
    int[cdouble] x;
    cdouble d=22.0+0.0i;
    x[d] = 44;
    if(44 != x[d]){
            assert(0);
    }
    return 0;
}