docs: fixed link to react-native-babel-transformer (#1158)

Summary:
The link was pointing to the old metro-react-native-babel-transformer (changed in #1024 to be located in the react-native repo)

Pull Request resolved: #1158

Test Plan: Link was pointing to a 404 and is now pointing to the correct location in the react-native repo

Reviewed By: huntie

Differential Revision: D52251534

Pulled By: robhogan

fbshipit-source-id: 2f41557805aa54e78062da46297762754a435de8

docs/Configuration.md

@@ -535,7 +535,7 @@ Type: `string`
 
 The name of a module that compiles code with Babel, returning an AST and optional metadata. Defaults to `metro-babel-transformer`.
 
-Refer to the source code of [`metro-babel-transformer`](https://github.com/facebook/metro/blob/main/packages/metro-babel-transformer/src/index.js) and [`metro-react-native-babel-transformer`](https://github.com/facebook/metro/blob/main/packages/metro-react-native-babel-transformer/src/index.js) for details on implementing a custom Babel transformer.
+Refer to the source code of [`metro-babel-transformer`](https://github.com/facebook/metro/blob/main/packages/metro-babel-transformer/src/index.js) and [`@react-native/metro-babel-transformer`](https://github.com/facebook/react-native/blob/main/packages/react-native-babel-transformer/src/index.js) for details on implementing a custom Babel transformer.
 
 :::note
 This option only has an effect under the default [`transformerPath`](#transformerpath). Custom transformers may ignore it.