Update README

Author: adamwathan

README.md

@@ -95,6 +95,7 @@ This library is very close to feature parity with `tailwindcss` currently and fo
 
 There are a few items on our todo list still though that we are still implementing:
 
-- The `prefix`, `important`, and `separator` options are not supported yet.
+- The `prefix` option is not supported yet.
+- The `important` option does not support strings like `#app` yet.
 - Advanced PurgeCSS options like `safelist` aren't supported yet since we aren't actually using PurgeCSS. We'll add a way to safelist classes for sure though.
 - You can only `@apply` classes that are part of core, generated by plugins, or defined within a `@layer` rule. You can't `@apply` arbitrary CSS classes that aren't defined within a `@layer` rule.