docopt.cr 1.4.0

Colored help: Docopt.colorizer= installs a hook applied to help text and usage-in-errors on terminals (NO_COLOR respected). require "docopt/color" adds Docopt.use_tartrazine_color, implementing the hook with tartrazine's docopt lexer in-process — never shelling out. Verified with escape-code assertions and wired into tartrazine's own CLI.