SpringBoot Properties from modules with only manual configuration metadata are not documented in the appendix

We have an infrastructure that gathers the generated file so that the documentation task can do what's necessary to generate the appendix.

While we don't have manual metadata in 3.5.x, we do for main and those are undocumented at the moment. https://github.com/spring-projects/spring-boot/issues/47984 has added a new plugin for this case and that should be updated to register those files too.

Comment From: wilkinsona

While we don't have manual metadata in 3.5.x

I've switched this issue to a task to reflect this. The forward port (#48095) remains a type: documentation issue.