Code style: move private constructors for singleton classes to the top of the file

nukkit/src/main/java/me/lucko/luckperms/nukkit/inject/permissible/PermissibleInjector.java

@@ -41,6 +41,7 @@ import java.util.Set;
  * checks made by plugins.
  */
 public final class PermissibleInjector {
+    private PermissibleInjector() {}
 
     /**
      * All permission checks made on standard Nukkit objects are effectively proxied to a
@@ -141,6 +142,4 @@ public final class PermissibleInjector {
         }
     }
 
-    private PermissibleInjector() {}
-
 }