Avoid broken links in documentation with a redirection as spring-security

[LeBezout]

Hi,

As already done for "spring-security" links, like this one https://docs.spring.io/spring-security/site/docs/current/reference/htmlsingle/#webflux-oauth2resourceserver-jwt-authorization a redirection can be implemented for the "spring-security-oauth2-boot" links to avoid broken ones.

Redirect https://docs.spring.io/spring-security-oauth2-boot/docs/current/reference/htmlsingle/* to https://docs.spring.io/spring-security-oauth2-boot/docs/current/reference/html5/*