return_num_moves: Return the number of moves in a game
Description
This function returns the number of moves played in each game. The function
accepts a vector of chess Moves data in PGN notation, usually called 'Moves'
Usage
return_num_moves(moves_string)
Value
A numeric vector of the number of moves in each game
Arguments
moves_string
A character vector of chess Moves data in PGN notation usually called 'Moves' in extracted data