public void GuessLetter(char letter)
{
if (!Word.Contains(letter))
{
Lives--;
}
else
{
int index = Word.IndexOf(letter);
while (index != -1)
{
var sb = new StringBuilder(RevealedLetters);
sb[index] = letter;
ValidateInput(letter);
RevealedLetters = sb.ToString();
index = Word.IndexOf(letter, index + 1);
}
}
}