This package comes with both a theme and a syntax lexer.
To install, copy lexers/moonscript.lua to a lexers directory in your local
textadept directory (usually .textadept).
To install the theme copy themes/moon.lua to a themes directory in your
local textadept directory.
Update your init.lua:
-- enable the lexer
local file_types = require "textadept.file_types"
file_types.extensions.moon = "moonscript"
-- enable the theme, with a custom font (optional)
ui.set_theme(CURSES and "term" or "moon", {
font = "Source Code Pro",
fontsize = 14,
})