Fix configuration property references in the reference docs

Previously, the configprop macro was being used in the source but the
extension that implements the macro was not available to Asciidoctor.
This led to the references not being checked at build time and the
macro being left as-is in the rendered documentation.

This commit updates the dependencies that are available to Asciidoctor
to include the extension and the projects which define the
configuration properties referenced in the documentation.

Closes gh-20149

Author: wilkinsona

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

@@ -8,16 +8,32 @@ plugins {
 
 configurations {
 	actuatorApiDocumentation
+	asciidoctorExtensions
 	autoConfiguration
 	configurationProperties
 	gradlePluginDocumentation
 	mavenPluginDocumentation
 	testSlices
 }
 
+repositories {
+	maven {
+		url "https://repo.spring.io/release"
+		mavenContent {
+			includeGroup "io.spring.asciidoctor"
+		}
+	}
+}
+
 dependencies {
 	actuatorApiDocumentation(project(path: ":spring-boot-project:spring-boot-actuator-autoconfigure", configuration: "documentation"))
 
+	asciidoctorExtensions(platform(project(":spring-boot-project:spring-boot-parent")))
+	asciidoctorExtensions("io.spring.asciidoctor:spring-asciidoctor-extensions-spring-boot")
+	asciidoctorExtensions(project(path: ":spring-boot-project:spring-boot-actuator-autoconfigure"))
+	asciidoctorExtensions(project(path: ":spring-boot-project:spring-boot-autoconfigure"))
+	asciidoctorExtensions(project(path: ":spring-boot-project:spring-boot-devtools"))
+
 	autoConfiguration(project(path: ":spring-boot-project:spring-boot-autoconfigure", configuration: "autoConfigurationMetadata"))
 	autoConfiguration(project(path: ":spring-boot-project:spring-boot-actuator-autoconfigure", configuration: "autoConfigurationMetadata"))
 	autoConfiguration(project(path: ":spring-boot-project:spring-boot-devtools", configuration: "autoConfigurationMetadata"))
@@ -111,7 +127,11 @@ task documentConfigurationProperties(type: org.springframework.boot.build.contex
 
 tasks.withType(org.asciidoctor.gradle.jvm.AbstractAsciidoctorTask) {
 	dependsOn dependencyVersions
+	configurations "asciidoctorExtensions"
 	baseDirFollowsSourceDir()
+	asciidoctorj {
+		fatalWarnings = ['^((?!successfully validated).)*$']
+	}
 	doFirst {
 		def versionConstraints = dependencyVersions.versionConstraints
 		attributes	"jetty-version": versionConstraints["org.eclipse.jetty:jetty-server"],