`CreateParams` get lost when calling any of the root-level methods

[santosmarco-caribou]

const MySchema = z.string({ description: 'this is a string schema' }).optional()
// => No longer has the description associated with it

This is because we are not passing the CreateParams to these methods on the root-level ZodType class.

Instead of:

nullable() {
  ZodNullable.create(this);
}

We should find a way to pass the CreateParams as well.

nullable() {
  ZodNullable.create(this, /* => */ params);
}