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 bug28;

void main()
{
    char[] a = "hello";
    char[] b = "hello";
    char[] c = "world";
    char[] d = "somethingelse";
    assert(a == a);
    assert(a == b);
    assert(a != c);
    assert(b != c);
    assert(a != d);
    assert(b != d);
    assert(c != d);
    assert(d == d);
}