docs: Separate javadocs per module

Core/build.gradle.kts

@@ -54,3 +54,13 @@ tasks.processResources {
         )
     }
 }
+
+tasks {
+    withType<Javadoc> {
+        val opt = options as StandardJavadocDocletOptions
+        opt.links("https://docs.enginehub.org/javadoc/com.sk89q.worldedit/worldedit-core/7.2.8/")
+        opt.links("https://jd.adventure.kyori.net/api/4.9.3/")
+        opt.links("https://google.github.io/guice/api-docs/5.0.1/javadoc/")
+        opt.links("https://checkerframework.org/api/")
+    }
+}