import { cinwords } from "https://deno.land/x/denops_std@v4.1.1/option/mod.ts";
These keywords start an extra indent in the next line when 'smartindent' or 'cindent' is set. For 'cindent' this is only done at an appropriate place (inside {}). Note that 'ignorecase' isn't used for 'cinwords'. If case doesn't matter, include the keyword both the uppercase and lowercase: "if,If,IF".