✨ Make the None class constructor public

There's no good reason for the `None` class constructor to be private.
We should let developers create new instances of `None` if they want.

src/option.ts

@@ -74,7 +74,7 @@ export class None extends OptionTrait {
 
   public override readonly isNone = true;
 
-  private constructor() {
+  public constructor() {
     super();
   }