Update validation.ts (#3324)

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### Change Type

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- [ ] `sdk` — Changes the tldraw SDK
- [ ] `dotcom` — Changes the tldraw.com web app
- [x] `docs` — Changes to the documentation, examples, or templates.
- [ ] `vs code` — Changes to the vscode plugin
- [ ] `internal` — Does not affect user-facing stuff

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- [ ] `bugfix` — Bug fix
- [ ] `feature` — New feature
- [ ] `improvement` — Improving existing features
- [x] `chore` — Updating dependencies, other boring stuff
- [ ] `galaxy brain` — Architectural changes
- [ ] `tests` — Changes to any test code
- [ ] `tools` — Changes to infrastructure, CI, internal scripts,
debugging tools, etc.
- [ ] `dunno` — I don't know


### Test Plan

N/A

- [ ] Unit Tests
- [ ] End to end tests

### Release Notes

- Update example for Union type

---

I believe this type was changed and `literal` is what it should be now.

packages/validate/src/lib/validation.ts

@@ -821,8 +821,8 @@ export function dict<Key extends string, Value>(
  * @example
  *
  * ```ts
- * const catValidator = T.object({ kind: T.value('cat'), meow: T.boolean })
- * const dogValidator = T.object({ kind: T.value('dog'), bark: T.boolean })
+ * const catValidator = T.object({ kind: T.literal('cat'), meow: T.boolean })
+ * const dogValidator = T.object({ kind: T.literal('dog'), bark: T.boolean })
  * const animalValidator = T.union('kind', { cat: catValidator, dog: dogValidator })
  * ```
  *