Add fuzzy autocomplete to /gamerule

With the change to the gamerule names in the most recent snapshot, it may take some time for users to get used to the new names.

The fuzzy autocomplete, which already exists in many other commands (i.e. /give, /effect, /enchant) would help immensely with the new change, so that when typing:

/gamerule weather

it shows the autocomplete option: advance_weather