Introduce ServerResponse Kotlin extensions

Issue: SPR-15293

Author: sdeleuze

spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/ServerResponseExtensions.kt

@@ -0,0 +1,11 @@
+package org.springframework.web.reactive.function.server
+
+import org.reactivestreams.Publisher
+
+/**
+ * Extension for [ServerResponse.BodyBuilder.body] providing a `body(Publisher<T>)` variant.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+inline fun <reified T : Any> ServerResponse.BodyBuilder.body(publisher: Publisher<T>) = body(publisher, T::class.java)