Mention productionRuntimeClasspath in the docs

Closes gh-27558

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/asciidoc/reacting.adoc

@@ -17,8 +17,9 @@ When Gradle's {java-plugin}[`java` plugin] is applied to a project, the Spring B
 5. Creates a {boot-run-javadoc}[`BootRun`] task named `bootRun` that can be used to run your application.
 6. Creates a configuration named `bootArchives` that contains the artifact produced by the `bootJar` task.
 7. Creates a configuration named `developmentOnly` for dependencies that are only required at development time, such as Spring Boot's Devtools, and should not be packaged in executable jars and wars.
-8. Configures any `JavaCompile` tasks with no configured encoding to use `UTF-8`.
-9. Configures any `JavaCompile` tasks to use the `-parameters` compiler argument.
+8. Creates a configuration named `productionRuntimeClasspath`. It is equivalent to `runtimeClasspath` minus any dependencies that only appear in the `developmentOnly` configuration.
+9. Configures any `JavaCompile` tasks with no configured encoding to use `UTF-8`.
+10. Configures any `JavaCompile` tasks to use the `-parameters` compiler argument.