fix docs

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

docs/auth/add-auth-provider.md

@@ -66,10 +66,6 @@ function takes an `express.Response`, a `WebMessageResponse` and the URL of the
 frontend (`appOrigin`) as parameters and return an HTML page with the script and
 the message.
 
-There is a helper class for [OAuth2](https://oauth.net/2/) based authentication providers, [OAuthAdapter](../reference/plugin-auth-node.oauthadapter.md). This class implements the `AuthProviderRouteHandlers` interface
-for you, and instead requires you to implement [OAuthHandlers](../reference/plugin-auth-node.oauthhandlers.md), which
-is significantly easier.
-
 ### Auth Environment Separation
 
 The concept of an `env` is core to the way the auth backend works. It uses an

docs/auth/identity-resolver--old.md

@@ -22,7 +22,7 @@ be mapped to user identities within Backstage.
 
 ## Quick Start
 
-> See [the auth docs](../index.md)
+> See [the auth docs](./index.md)
 > for a full list of auth providers and their built-in sign-in resolvers.
 
 Backstage projects created with `npx @backstage/create-app` come configured with a