docs: Added missing bracket to README (#195)

Added missing bracket to example setup options in README.

README.md

@@ -146,7 +146,7 @@ require("tokyonight").setup({
   ---@param highlights Highlights
   ---@param colors ColorScheme
   on_highlights = function(highlights, colors) end,
-}
+})
 ```
 
 Example for changing some settings and colors