Use shorthand rootDir and buildDir methods

Signed-off-by: Graham <gpe@openrs2.dev>

all/build.gradle.kts

@@ -65,14 +65,14 @@ distributions {
     all {
         contents {
             from("$buildDir/AUTHORS")
-            from("${rootProject.projectDir}/DCO")
-            from("${rootProject.projectDir}/LICENSE")
-            from("${rootProject.projectDir}/README.md")
-            from("${rootProject.projectDir}/etc/config.example.yaml") {
+            from("$rootDir/DCO")
+            from("$rootDir/LICENSE")
+            from("$rootDir/README.md")
+            from("$rootDir/etc/config.example.yaml") {
                 rename { "config.yaml" }
                 into("etc")
             }
-            from("${rootProject.projectDir}/share") {
+            from("$rootDir/share") {
                 exclude(".*", "*~")
                 into("share")
             }

build.gradle.kts

@@ -40,7 +40,7 @@ allprojects {
     plugins.withType<ApplicationPlugin> {
         tasks.named<JavaExec>("run") {
             standardInput = System.`in`
-            workingDir = rootProject.projectDir
+            workingDir = rootDir
         }
     }
 
@@ -212,7 +212,7 @@ fun commitHash(): String {
 }
 
 tasks.dokka {
-    outputDirectory = "${project.buildDir}/kdoc"
+    outputDirectory = "$buildDir/kdoc"
     outputFormat = "html"
 
     subProjects = subprojects.filter { it.isFree && it.name != "deob-annotations" }.map { it.name }