Fix links to Maven Plugin's documentation in reference guide

Closes gh-20818

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

@@ -29,7 +29,9 @@
 :spring-boot-master-code: https://github.com/{github-repo}/tree/master
 :spring-boot-current-docs: https://docs.spring.io/spring-boot/docs/current/reference/
 :spring-boot-actuator-restapi: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/actuator-api/
-:spring-boot-maven-plugin-docs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/maven-plugin/html/
+:spring-boot-maven-plugin-docs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/maven-plugin/reference/html/
+:spring-boot-maven-plugin-pdfdocs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/maven-plugin/reference/pdf/spring-boot-gradle-plugin-reference.pdf
+:spring-boot-maven-plugin-api: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/maven-plugin/api/
 :spring-boot-gradle-plugin-docs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/gradle-plugin/reference/html/
 :spring-boot-gradle-plugin-pdfdocs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/gradle-plugin/reference/pdf/spring-boot-gradle-plugin-reference.pdf
 :spring-boot-gradle-plugin-api: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/gradle-plugin/api/

spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins.adoc

@@ -14,7 +14,10 @@ If you are just getting started, you might want to read "`<<using-spring-boot.ad
 The Spring Boot Maven Plugin provides Spring Boot support in Maven, letting you package executable jar or war archives and run an application "`in-place`".
 To use it, you must use Maven 3.2 (or later).
 
-NOTE: See the {spring-boot-maven-plugin-docs}[Spring Boot Maven Plugin Documentation] for complete plugin documentation.
+Please refer to the plugin's documentation to learn more:
+
+* Reference ({spring-boot-maven-plugin-docs}[HTML] and {spring-boot-maven-plugin-pdfdocs}[PDF])
+* {spring-boot-maven-plugin-api}[API]