docs(docs-infra): change variable names in route guards examples (#44444)

change variable name 'next' to 'route' in route guards examples on developer guides "Routing and Navigation Tutorial: Adding routing to Tour of Heroes" to make it consistent with api docs and subsequent examples.

Fixes #44291

PR Close #44444

aio/content/examples/router/src/app/auth/auth.guard.1.ts

@@ -7,7 +7,7 @@ import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angul
 })
 export class AuthGuard implements CanActivate {
   canActivate(
-    next: ActivatedRouteSnapshot,
+    route: ActivatedRouteSnapshot,
     state: RouterStateSnapshot): boolean {
     console.log('AuthGuard#canActivate called');
     return true;

aio/content/examples/router/src/app/auth/auth.guard.2.ts

@@ -11,7 +11,7 @@ export class AuthGuard implements CanActivate {
   constructor(private authService: AuthService, private router: Router) {}
 
   canActivate(
-    next: ActivatedRouteSnapshot,
+    route: ActivatedRouteSnapshot,
     state: RouterStateSnapshot): true|UrlTree {
     const url: string = state.url;