Only append "Service" suffix when services are not properly named.

Protobuf services should end in `Service`. This is a [buf lint rule](https://github.com/bufbuild/buf-examples/blob/main/linting/bad/acme/weather/v1/weather.proto#L39), recommended via [the protobuf style guide](https://developers.google.com/protocol-buffers/docs/style#services), and demonstrated in [Twirp Best Practices](https://twitchtv.github.io/twirp/docs/best_practices.html))

Therefore, we only append "Service" to fixup services that are not well named. This avoids generating e.g. "MessagesServiceService".

protoc-gen-twirp_ruby/main.go

@@ -109,7 +109,12 @@ func (g *generator) generateRubyCode(file *descriptor.FileDescriptorProto, pbFil
 	for i, service := range file.Service {
 		svcName := service.GetName()
 
-		print(b, "%sclass %sService < ::Twirp::Service", indent, camelCase(svcName))
+		// Well-named services already end in "Service"; fixup services that don't.
+		if !strings.HasSuffix(svcName, "Service") {
+			svcName += "Service"
+		}
+
+		print(b, "%sclass %s < ::Twirp::Service", indent, camelCase(svcName))
 		if pkgName != "" {
 			print(b, "%s  package '%s'", indent, pkgName)
 		}
@@ -125,7 +130,7 @@ func (g *generator) generateRubyCode(file *descriptor.FileDescriptorProto, pbFil
 		print(b, "")
 
 		print(b, "%sclass %sClient < ::Twirp::Client", indent, camelCase(svcName))
-		print(b, "%s  client_for %sService", indent, camelCase(svcName))
+		print(b, "%s  client_for %s", indent, camelCase(svcName))
 		print(b, "%send", indent)
 		if i < len(file.Service)-1 {
 			print(b, "")