Set StaticMembers as internal

src/index.ts

@@ -5,7 +5,7 @@ import { AbstractClass, AbstractConstructor, Opaque, UnionToIntersection } from
  * Represents the static members of a class.
  * @template C - The class type.
  */
-export type StaticMembers<C> = {
+type StaticMembers<C> = {
     [Key in keyof C as Key extends "prototype" ? never : Key]: C[Key]
 }