Update links to Micrometer reference docs

See gh-39114

Author: tobias-lippert

spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/metrics.adoc

@@ -22,7 +22,7 @@ Spring Boot Actuator provides dependency management and auto-configuration for h
 - <<actuator#actuator.metrics.export.statsd,StatsD>>
 - <<actuator#actuator.metrics.export.wavefront,Wavefront>>
 
-TIP: To learn more about Micrometer's capabilities, see its https://micrometer.io/docs[reference documentation], in particular the {micrometer-concepts-docs}[concepts section].
+TIP: To learn more about Micrometer's capabilities, see its {micrometer-docs}[reference documentation], in particular the {micrometer-concepts-docs}[concepts section].
 
 
 

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

@@ -106,7 +106,7 @@
 :junit5-docs: https://junit.org/junit5/docs/current/user-guide
 :kotlin-docs: https://kotlinlang.org/docs/reference/
 :lettuce-docs: https://lettuce.io/core/{lettuce-version}/reference/index.html
-:micrometer-docs: https://micrometer.io/docs
+:micrometer-docs: https://docs.micrometer.io/micrometer/reference
 :micrometer-concepts-docs: {micrometer-docs}/concepts
 :micrometer-registry-docs: {micrometer-docs}/registry
 :tomcat-docs: https://tomcat.apache.org/tomcat-{tomcat-version}-doc