SpringBoot Update javadoc to reflect move from WebSecurityConfigurerAdapter to SecurityFilterChain

We moved to SecurityFilterChain in https://github.com/spring-projects/spring-boot/commit/0818f27f44317c52f66b9f0e7030fa8fcb7a92f0 but the changes for https://github.com/spring-projects/spring-boot/issues/29897 have revealed that some javadoc updates were missed.

Comment From: wilkinsona

Some public javadoc is affected, for example the description of org.springframework.boot.autoconfigure.security.SecurityProperties.BASIC_AUTH_ORDER.