Fix godoc in suite_test template of testing plugin

[tchssk]

This pull request updates the naming conventions for generated test harness helpers and their documentation comments to use proper Go-style capitalization and struct names, improving consistency and readability across the codebase.

Test harness naming and documentation consistency:

• Updated the documentation comment in suite_test.go.tpl to use .Service.StructName instead of .Service.Name, ensuring the generated comment references the correct struct name.
• Corrected the function name and comment in calculator_suite_test.go from RuncalculatorHarness to RunCalculatorHarness, matching Go naming conventions.
• Corrected the function name and comment in test_http_grpc_suite_test.go from Runtest-http-grpcHarness to RunTestHTTPGrpcHarness, using proper capitalization and removing dashes.
• Corrected the function name and comment in test_jsonrpc_suite_test.go from Runtest-jsonrpcHarness to RunTestJsonrpcHarness, using proper capitalization and removing dashes.

[raphael]

This is great, thank you!