Docs: fixer-return in readme.md

Author: aladdin-add

README.md

@@ -49,6 +49,7 @@ Then configure the rules you want to use under the rules section.
 Name | ✔️ | 🛠 | Description
 ----- | ----- | ----- | -----
 [consistent-output](https://github.com/not-an-aardvark/eslint-plugin-eslint-plugin/blob/master/docs/rules/consistent-output.md) | | | Enforces consistent use of output assertions in rule tests
+[fixer-return](https://github.com/not-an-aardvark/eslint-plugin-eslint-plugin/blob/master/docs/rules/fixer-return.md) | | | Enforces always return from a fixer function
 [no-deprecated-report-api](https://github.com/not-an-aardvark/eslint-plugin-eslint-plugin/blob/master/docs/rules/no-deprecated-report-api.md) | ✔️ | 🛠 | Prohibits the deprecated `context.report(node, message)` API
 [no-identical-tests](https://github.com/not-an-aardvark/eslint-plugin-eslint-plugin/blob/master/docs/rules/no-identical-tests.md) | | 🛠 | Disallows identical tests
 [no-missing-placeholders](https://github.com/not-an-aardvark/eslint-plugin-eslint-plugin/blob/master/docs/rules/no-missing-placeholders.md) | ✔️ | | Disallows missing placeholders in rule report messages