\r\n is not normalized to \n by TextBlock

[Jeremy-Price]

https://www.toptensoftware.com/richtextkit/basics claims that \r\n is normalized to \n, but doing something like

TextBlock tb = new TextBlock();
tb.AddText("X \n Y \r\n Z", style);

renders as

X
Y□
Z

[ivan-h-ivanov]

Check #53