Add section about Kafka metrics support

Closes gh-21910

spring-boot-project/spring-boot-docs/build.gradle

@@ -189,6 +189,7 @@ tasks.withType(org.asciidoctor.gradle.jvm.AbstractAsciidoctorTask) {
 					"spring-data-rest-version": versionConstraints["org.springframework.data:spring-data-rest-core"],
 					"spring-data-solr-version": versionConstraints["org.springframework.data:spring-data-solr"],
 					"spring-framework-version": versionConstraints["org.springframework:spring-core"],
+					"spring-kafka-version": versionConstraints["org.springframework.kafka:spring-kafka"],
 					"spring-integration-version": versionConstraints["org.springframework.integration:spring-integration-core"],
 					"spring-security-version": versionConstraints["org.springframework.security:spring-security-core"],
 					"spring-webservices-version": versionConstraints["org.springframework.ws:spring-ws-core"]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/attributes.adoc

@@ -86,6 +86,7 @@
 :spring-initializr-docs: https://docs.spring.io/initializr/docs/current/reference/html
 :spring-integration: https://spring.io/projects/spring-integration
 :spring-integration-docs: https://docs.spring.io/spring-integration/docs/{spring-integration-version}/reference/html/
+:spring-kafka-docs: https://docs.spring.io/spring-kafka/docs/{spring-kafka-version}/reference/html/
 :spring-restdocs: https://spring.io/projects/spring-restdocs
 :spring-security: https://spring.io/projects/spring-security
 :spring-security-docs: https://docs.spring.io/spring-security/site/docs/{spring-security-version}/reference/html5/

spring-boot-project/spring-boot-docs/src/docs/asciidoc/production-ready-features.adoc

@@ -1820,7 +1820,7 @@ Spring Boot registers the following core metrics when applicable:
 ** Number of classes loaded/unloaded
 * CPU metrics
 * File descriptor metrics
-* Kafka consumer metrics
+* Kafka consumer and producer metrics
 * Log4j2 metrics: record the number of events logged to Log4j2 at each level
 * Logback metrics: record the number of events logged to Logback at each level
 * Uptime metrics: report a gauge for uptime and a fixed gauge representing the application's absolute start time
@@ -2069,6 +2069,13 @@ Auto-configuration will enable the instrumentation of all available RabbitMQ con
 
 
 
+[[production-ready-metrics-kafka]]
+==== Kafka Metrics
+Auto-configuration will register a `MicrometerConsumerListener` and `MicrometerProducerListener` for the auto-configured consumer factory and producer factory respectively.
+For more details refer to {spring-kafka-docs}#micrometer-native[Micrometer Native Metrics] section of the Spring Kafka documentation.
+
+
+
 [[production-ready-metrics-custom]]
 === Registering custom metrics
 To register custom metrics, inject `MeterRegistry` into your component, as shown in the following example:

spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc

@@ -5728,7 +5728,7 @@ IMPORTANT: Properties set in this way override any configuration item that Sprin
 ==== Testing with Embedded Kafka
 Spring for Apache Kafka provides a convenient way to test projects with an embedded Apache Kafka broker.
 To use this feature, annotate a test class with `@EmbeddedKafka` from the `spring-kafka-test` module.
-For more information, please see the Spring for Apache Kafka https://docs.spring.io/spring-kafka/docs/current/reference/html/#embedded-kafka-annotation[reference manual].
+For more information, please see the Spring for Apache Kafka {spring-kafka-docs}#embedded-kafka-annotation[reference manual].
 
 To make Spring Boot auto-configuration work with the aforementioned embedded Apache Kafka broker, you need to remap a system property for embedded broker addresses (populated by the `EmbeddedKafkaBroker`) into the Spring Boot configuration property for Apache Kafka.
 There are several ways to do that: