Update auth.md change user$ = user(auth); to user$ = user(this.auth);

This PR fixes an issue in the AngularFire documentation where the auth instance is incorrectly referenced in user(auth). The correct approach is to use the injected auth instance (this.auth) instead. The updated code ensures proper dependency injection and aligns with best practices in Angular.

Author: arolleaguekeng

docs/auth.md

@@ -106,7 +106,7 @@ import { Auth, User, user } from '@angular/fire/auth';
 
 export class UserComponent implements OnDestroy {
   private auth: Auth = inject(Auth);
-  user$ = user(auth);
+  user$ = user(this.auth);
   userSubscription: Subscription;
   ...
 
@@ -136,7 +136,7 @@ import { Auth, authState } from '@angular/fire/auth';
 
 export class UserComponent implements OnDestroy {
   private auth: Auth = inject(Auth);
-  authState$ = authState(auth);
+  authState$ = authState(this.auth);
   authStateSubscription: Subscription;
   ...
 
@@ -165,7 +165,7 @@ import { Auth, idToken } from '@angular/fire/auth';
 
 export class UserComponent implements OnDestroy {
   private auth: Auth = inject(Auth);
-  idToken$ = idToken(auth);
+  idToken$ = idToken(this.auth);
   idTokenSubscription: Subscription;
   ...