Add 'MarkdownDescriptionService' examples for 'annotated-http-service…

…-kotlin'

examples/annotated-http-service-kotlin/src/main/kotlin/example/armeria/server/annotated/kotlin/Main.kt

@@ -50,6 +50,8 @@ fun configureServices(sb: ServerBuilder) {
         .build(DecoratingService())
         // DocService
         .serviceUnder("/docs", DocService())
+        // MarkdownDescriptionService
+        .annotatedService(MarkdownDescriptionService())
 }
 
 private fun AnnotatedServiceBindingBuilder.applyCommonDecorator(): AnnotatedServiceBindingBuilder {

examples/annotated-http-service-kotlin/src/main/kotlin/example/armeria/server/annotated/kotlin/MarkdownDescriptionService.kt

@@ -0,0 +1,77 @@
+package example.armeria.server.annotated.kotlin
+
+import com.linecorp.armeria.server.annotation.Description
+import com.linecorp.armeria.server.annotation.Get
+import com.linecorp.armeria.server.annotation.Param
+import org.slf4j.LoggerFactory
+
+@CoroutineNameDecorator(name = "default")
+class MarkdownDescriptionService {
+    @Description("""
+        ## Support markdown
+        ### Support header
+        - support lists
+        
+        ### Support code-highlight
+        ```java
+        Server
+          .builder()
+          .service(
+            "/hello",
+            (ctx, req) -> HttpResponse.of("Hello!"))
+          .service(GrpcService
+            .builder()
+            .addService(myGrpcServiceImpl)
+            .build())
+          .service(
+            "/api/thrift",
+            ThriftService.of(myThriftServiceImpl))
+          .service(
+            "prefix:/files",
+            FileService.of(new File("/var/www")))
+          .service(
+            "/monitor/l7check",
+            HealthCheckService.of())
+          .build()
+          .start();
+        ```
+    """)
+    @Get("/markdown")
+    fun markdown(
+            @Description("""
+            `Param` description
+            """)
+            @Param param1: String,
+            @Param param2: String,
+            @Description("param3 description")
+            @Param param3: MarkdownEnumParam
+    ): MarkdownDescriptionResult {
+        return MarkdownDescriptionResult(
+                result1 = "foo",
+                result2 = "bar",
+                result3 = "hello"
+        )
+    }
+
+    @Description("""
+        ## Structs description
+        ### Structs description subtitle
+        > support quotes
+    """)
+    data class MarkdownDescriptionResult(
+        @field:Description("result1 description (default)")
+        val result1: String,
+        @field:Description("`result2` **description** (use markdown)")
+        val result2: String,
+        @field:Description("`result3` see https://armeria.dev/ (add links)")
+        val result3: String
+    )
+
+    @Description("MarkdownEnumParam")
+    enum class MarkdownEnumParam {
+        @field:Description("Description for `ENUM_1`")
+        ENUM_1,
+        ENUM_2,
+        ENUM_3
+    }
+}