Buck2 completion support for fish

buck2.fish

# put this in ~/.config/fish/conf.d/buck2.fish
set -g __buck2_completion_loaded false

function __check_buck2_availability --on-variable PATH
    if $__buck2_completion_loaded
        return
    end

    if command -q buck2
        buck2 completion fish | source
        set -g __buck2_completion_loaded true
    end
end