feat: add ability to specify custom kinds

[prevwong]

This PR adds the ability for consumers to specify custom variable kinds:

Reka.create({
   kinds: {
      Color: {
          fallback: "#000",
          validate: field => field.string(value => isValidColor(value))
       }
   }
});

t.val({ 
  name: "color",
  kind: t.customKind({ name: "Color" }),
  init: t.literal({ value: "#000" })
});

// color: Color = "#000";

Note: Validation is not currently handled in this PR. Hence much of the APIs above are purely decorative at the moment.

[changeset-bot]

🦋 Changeset detected

Latest commit: 3631849

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@rekajs/parser	Patch
@rekajs/types	Patch
@rekajs/core	Patch

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Name	Status	Preview	Updated (UTC)
reka	✅ Ready (Inspect)	Visit Preview	Dec 18, 2023 4:59pm