Use configuration avoidance APIs in Gradle plugin's docs

Closes gh-30056

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-disable-optimized-launch.gradle

@@ -4,12 +4,12 @@ plugins {
 }
 
 // tag::launch[]
-bootRun {
+tasks.named("bootRun") {
 	optimizedLaunch = false
 }
 // end::launch[]
 
-task optimizedLaunch {
+tasks.register("optimizedLaunch") {
 	doLast {
 		println bootRun.optimizedLaunch
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-disable-optimized-launch.gradle.kts

@@ -6,12 +6,12 @@ plugins {
 }
 
 // tag::launch[]
-tasks.getByName<BootRun>("bootRun") {
+tasks.named<BootRun>("bootRun") {
 	isOptimizedLaunch = false
 }
 // end::launch[]
 
-task("optimizedLaunch") {
+tasks.register("optimizedLaunch") {
 	doLast {
 		println(tasks.getByName<BootRun>("bootRun").isOptimizedLaunch)
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-main.gradle

@@ -4,12 +4,12 @@ plugins {
 }
 
 // tag::main[]
-bootRun {
+tasks.named("bootRun") {
 	mainClass = 'com.example.ExampleApplication'
 }
 // end::main[]
 
-task configuredMainClass {
+tasks.register("configuredMainClass") {
 	doLast {
 		println bootRun.mainClass
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-main.gradle.kts

@@ -6,12 +6,12 @@ plugins {
 }
 
 // tag::main[]
-tasks.getByName<BootRun>("bootRun") {
+tasks.named<BootRun>("bootRun") {
 	mainClass.set("com.example.ExampleApplication")
 }
 // end::main[]
 
-task("configuredMainClass") {
+tasks.register("configuredMainClass") {
 	doLast {
 		println(tasks.getByName<BootRun>("bootRun").mainClass)
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-source-resources.gradle

@@ -4,12 +4,12 @@ plugins {
 }
 
 // tag::source-resources[]
-bootRun {
+tasks.named("bootRun") {
 	sourceResources sourceSets.main
 }
 // end::source-resources[]
 
-task configuredClasspath {
+tasks.register("configuredClasspath") {
 	doLast {
 		println bootRun.classpath.files
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-source-resources.gradle.kts

@@ -6,12 +6,12 @@ plugins {
 }
 
 // tag::source-resources[]
-tasks.getByName<BootRun>("bootRun") {
+tasks.named<BootRun>("bootRun") {
 	sourceResources(sourceSets["main"])
 }
 // end::source-resources[]
 
-task("configuredClasspath") {
+tasks.register("configuredClasspath") {
 	doLast {
 		println(tasks.getByName<BootRun>("bootRun").classpath.files)
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-system-property.gradle

@@ -4,12 +4,12 @@ plugins {
 }
 
 // tag::system-property[]
-bootRun {
+tasks.named("bootRun") {
 	systemProperty 'com.example.property', findProperty('example') ?: 'default'
 }
 // end::system-property[]
 
-task configuredSystemProperties {
+tasks.register("configuredSystemProperties") {
 	doLast {
 		bootRun.systemProperties.each { k, v -> 
 			println "$k = $v"

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/boot-run-system-property.gradle.kts

@@ -6,14 +6,14 @@ plugins {
 }
 
 // tag::system-property[]
-tasks.getByName<BootRun>("bootRun") {
+tasks.named<BootRun>("bootRun") {
 	systemProperty("com.example.property", findProperty("example") ?: "default")
 }
 // end::system-property[]
 
-task("configuredSystemProperties") {
+tasks.register("configuredSystemProperties") {
 	doLast {
-		tasks.getByName<BootRun>("bootRun").systemProperties.forEach { k, v -> 
+		tasks.getByName<BootRun>("bootRun").systemProperties.forEach { k, v ->
 			println("$k = $v")
 		}
 	}