Given a 3×3 matrix (an array of arrays) representing a completed Tic-Tac-Toe game, determine the winner.
- Each element in the given matrix is either an
"X" or "O".
A player wins if they have three of their characters in a row - horizontally, vertically, or diagonally.
Return:
"X wins" if player X has three in a row."O wins" if player O has three in a row."Draw" if no player has three in a row.