Extract Javadoc of a request and a response object in an annotated service for the documantation of DocService

[ikhoon]

Currently, @param in a Javadoc of an annotated service is extracted and exposed to DocService.

armeria/annotation-processor/src/main/java/com/linecorp/armeria/server/annotation/processor/DocumentationProcessor.java

Line 154 in 92f5d0a

if (docComment == null || !docComment.contains("@param")) {

Thanks to #4304, we can annotate @Description to the fields of a class. On top of that, it is also useful if we can use the Javadocs in a request and a response object as descriptions for StructInfo, EnumInfo, and ExceptionInfo.