Adding help command

[grantcollins1]

When a user enters 'h', they will see a statement that explains how to play the game and which keys they can use to quit, restart, and play the game. They can then press any key to continue playing the game. This will provide a new user with a more helpful interface when they start playing the game.

[ulcuber]

It is a breaking change. h is used for vim style arrows. Consider ?