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 switch2;
extern(C) int printf(char*, ...);

void main()
{
    int i = 2;
    switch(i)
    {
    case 0: assert(0);
    case 1,2: printf("hello world\n"); break;
    default: assert(0);
    }
}