Use full method signature for docstring keys

[coderabbitai]

Problem

Currently, docstring keys use only the class name and method name, causing overloaded methods to share the same key and overwrite each other's descriptions.

Current format: <fqcn>/<method>

This causes issues when multiple overloaded methods have different @ReturnDescription, @ThrowsDescription, or parameter descriptions, as they all map to the same key.

Proposed Solution

Update docstring key format to include the full method signature:

Desired format: <fqcn>/<method>(<method_signature>)

Example: com.example.MyService/myMethod(com.example.FirstParam,com.example.SecondParam)

Additional Requirements

• Always use fully-qualified class names (FQCN) for:
  • Parameter types in method signatures
  • Return types in :return keys
  • Exception types in :throws/ keys

Example Keys

• Method description: com.example.MyService/myMethod(java.lang.String,int)
• Return description: com.example.MyService/myMethod(java.lang.String,int):return
• Exception description: com.example.MyService/myMethod(java.lang.String,int):throws/com.example.CustomException
• Parameter description: com.example.MyService/myMethod(java.lang.String,int):param/paramName

Implementation Notes

This involves two related fixes:

1. Incorporating method signature into keys to distinguish overloads
2. Ensuring FQCN usage throughout all docstring key components

Both should be handled together as they are interrelated.

Context

• Related PR: Add docstring support for return types and exception types in MethodInfo #6605
• Comment thread: Add docstring support for return types and exception types in MethodInfo #6605 (comment)

Affected Code

• core/src/main/java/com/linecorp/armeria/internal/server/annotation/AnnotatedDocServicePlugin.java
  • extractMethodDescription()
  • extractReturnDescription()
  • extractThrowsDescriptions()
  • extractParameterDescriptions()
• Similar patterns in gRPC and Thrift plugins may need updating
• Properties file format and parsing logic
• UI/client code that looks up docstrings by key