unicode grapheme test

unicode.d

import std;
import std.utf;
import std.uni;
import std.range.primitives : walkLength;
import std.range : take, drop;

void main()
{
    auto s2 = "\U0001f9db\u200d\u2640"; // this is a female vampire (vampire + ZWJ + female)
	auto wr = byGrapheme(s2);
    writefln("s2 is %s\n", s2); 
    writefln("graphemes %d (expect 1)\n", wr.walkLength); // this should be "1"
    
    s2 = "\U0001f1fa\U0001f1f8"; // flag modified with USA, displays as US flag
    wr = byGrapheme(s2);
    writefln("s2 is %s\n", s2); 
    writefln("graphemes %d (expect 1)\n", wr.walkLength); // this should be "1"
}