commands: use relative frequencies of letters in acrophobia
commands: use relative frequencies of letters in acrophobia

Bastion will now use relative frequencies of letters, as the first
letter of an English word, to generate acronyms for the acrophobia
game.

Closes: https://github.com/TheBastionBot/Bastion/issues/426

snkrsnkampa/Bastion,snkrsnkampa/Bastion