chore(docs): Fix broken link in docs/Guide.md (#1436 by @Sappphire64)

[skip ci]

docs/Guide.md

 
 You can set cookies on the React Native side using the [@react-native-community/cookies](https://github.com/react-native-community/cookies) package.
 
-When you do, you'll likely want to enable the [sharedCookiesEnabled](Reference#sharedCookiesEnabled) prop as well.
+When you do, you'll likely want to enable the [sharedCookiesEnabled](Reference.md#sharedCookiesEnabled) prop as well.
 
 ```jsx
 const App = () => {