Update Javadocs with @snippet tags.

Change-Id: I22f440c6ced5b90cdebc1fdf068171e7baad180f
diff --git a/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java b/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java
index 70bdce6..b8f80ce 100644
--- a/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java
+++ b/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java
@@ -15,7 +15,7 @@
  *
  * <p><strong>Example:</strong>
  *
- * <pre>{@code
+ * {@snippet :
  * @Singleton
  * @Unremovable
  * public final class TraceLogParameterProvider implements StructuredParameterProvider {
@@ -28,11 +28,11 @@
  *     return () -> b;
  *   }
  * }
- * }</pre>
+ * }
  *
  * Result:
  *
- * <pre>{@code
+ * {@snippet lang="json" :
  * {
  *   "jsonPayload": {
  *     "message": "Request rejected: unauthorized.",
@@ -40,7 +40,7 @@
  *     "spanId": "c7431b14630b633d"
  *   }
  * }
- * }</pre>
+ * }
  *
  * @see LabelProvider
  */