Fix incorrect class reference syntax in Kotlin code sample

Closes gh-32733

Author: Seungpang

framework-docs/modules/ROOT/pages/testing/webtestclient.adoc

@@ -672,13 +672,13 @@ Kotlin::
 	val result = client.get().uri("/persons/1")
 			.exchange()
 			.expectStatus().isOk()
-			.expectBody(Person.class)
-			.returnResult();
+			.expectBody(Person::class.java)
+			.returnResult()
 
 	// For a response without a body
 	val result = client.get().uri("/path")
 			.exchange()
-			.expectBody().isEmpty();
+			.expectBody().isEmpty()
 ----
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