Default value of server.jetty.accesslog.format is wrongly associated to server.forward-headers-strategy

[cniesen]

The generated documentation for ServerProperties isn't correct.
server.jetty.accesslog.format default should be "ncsa" while
server.forward-headers-strategy should shouldn't have a default. At least I couldn't find in code where that property is initialized.

Relevant code snippets:

• https://github.com/spring-projects/spring-boot/blob/v2.3.2.RELEASE/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java#L1182
• https://github.com/spring-projects/spring-boot/blob/v2.3.2.RELEASE/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java#L91

[snicoll]

Thanks for the report. This is a polish commit that unfortunately mixed things up