refer to the right docs in create-app backend index

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

.changeset/soft-horses-lie.md

@@ -0,0 +1,5 @@
+---
+'@backstage/create-app': patch
+---
+
+Fix docs reference

packages/create-app/templates/default-app/packages/backend/src/index.ts

@@ -19,7 +19,7 @@ backend.add(import('@backstage/plugin-techdocs-backend/alpha'));
 backend.add(import('@backstage/plugin-auth-backend'));
 // See https://backstage.io/docs/backend-system/building-backends/migrating#the-auth-plugin
 backend.add(import('@backstage/plugin-auth-backend-module-guest-provider'));
-// See https://github.com/backstage/backstage/blob/master/docs/auth/guest/provider.md
+// See https://backstage.io/docs/auth/guest/provider
 
 // catalog plugin
 backend.add(import('@backstage/plugin-catalog-backend/alpha'));