Update to user-guide.md - fix sign-in-page switch

[snowjet]

Incorrect Documentation - should be "sign-in-page" not "sign-page".

Update to user-guide.md - fix sign-in-page switch

Summary

The documentation incorrectly states the switch to use a custom sign in pages as signin-page. This should be sign-in-page.

Type

[] Bug fix
[] Feature request
[] Enhancement
[X] Docs

Why?

Incorrect documentation should be fixed.

Requirements

How to try it?

discovery-url: https://keycloak.example.com/auth/realms/<REALM_NAME>
client-id: <CLIENT_ID>
client-secret: <CLIENT_SECRET>
listen: :3000
enable-refresh-tokens: true
tls-cert:
tls-private-key:
redirection-url: http://127.0.0.1:3000
encryption-key: <ENCRYPTION_KEY>
upstream-url: http://127.0.0.1:80
forbidden-page: /html/forbidden.html
sign-in-page: /html/signin.html
resources:
  - uri: /

Documentation

Additional Information

Checklist:

• My change requires a change to the documentation or CHANGELOG.
• [ x ] I have updated the documentation/CHANGELOG accordingly.

[abstractj]

@snowjet thank you!