update prettier options doc

Author: patricklx

README.md

@@ -49,22 +49,9 @@ module.exports = {
 The recommended set will apply [these rules](https://github.com/ember-template-lint/ember-template-lint-plugin-prettier/blob/v1.1.0-beta.0/lib/config/recommended.js).
 
 ## Configure Prettier Options
+Prettier can only be configured via [standard prettier config files](https://prettier.io/docs/en/configuration.html)
+It is not possible to pass prettier options with the rule options.
 
-Prettier can be configured via [standard prettier config files](https://prettier.io/docs/en/configuration.html), or rule config options.
-The configuration from the rule will be merged with the rc file config, overriding existing options.
-e.g
-
-```js
-module.exports = {
-  plugins: ["ember-template-lint-plugin-prettier"],
-
-  extends: ["recommended", "ember-template-lint-plugin-prettier:recommended"],
-  
-  rules: {
-    "prettier": { singleQuote: true }
-  }
-};
-```
 
 ## Tips