[ci skip] Move generated API sources to src/generated/java (#11977)

This removes a required patch set for forks.

paper-api-generator/build.gradle.kts

@@ -25,7 +25,7 @@ tasks.register<JavaExec>("generate") {
     dependsOn(tasks.check)
     mainClass.set("io.papermc.generator.Main")
     classpath(sourceSets.main.map { it.runtimeClasspath })
-    args(projectDir.toPath().resolve("generated").toString())
+    args(rootProject.layout.projectDirectory.dir("paper-api/src/generated/java").asFile.absolutePath)
     javaLauncher = javaToolchains.defaultJavaLauncher(project)
 }
 

paper-api/build.gradle.kts

@@ -93,7 +93,7 @@ dependencies {
     testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }
 
-val generatedApiPath: java.nio.file.Path = rootProject.projectDir.toPath().resolve("paper-api-generator/generated")
+val generatedApiPath: java.nio.file.Path = layout.projectDirectory.dir("src/generated/java").asFile.toPath()
 idea {
     module {
         generatedSourceDirs.add(generatedApiPath.toFile())