Update scalar types docs

| `xsd:dateTime`           | [`Temporal.Instant`]                              |

| `xsd:duration`           | [`Temporal.Duration`]                             |

| `rdf:langString`         | `LanguageString`                                  |

| `w3id:cryptosuiteString` | `"eddsa-jcs-2022"`                                |

| `w3id:multibase`         | [`Uint8Array`]                                    |

| Language tag ([BCP 47])  | [`LanguageTag`]                                   |

| Public key PEM           | [`CryptoKey`]                                     |

| Public key Multibase     | [`CryptoKey`]                                     |

| Proof purpose            | `"assertionMethod" \| "authentication" \| "capabilityInvocation" \| "capabilityDelegation" \| "keyAgreement"` |

| Units                    | `"cm" \| "feet" \| "inches" \| "km" \| "m" \| "miles" \| URL` |

[`URL`]: https://developer.mozilla.org/en-US/docs/Web/API/URL

[`Temporal.Instant`]: https://tc39.es/proposal-temporal/docs/instant.html

[`Temporal.Duration`]: https://tc39.es/proposal-temporal/docs/duration.html

[`Uint8Array`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array

[BCP 47]: https://www.rfc-editor.org/info/bcp47

[`LanguageTag`]: https://phensley.github.io/cldr-engine/docs/en/api-languagetag

[`CryptoKey`]: https://developer.mozilla.org/en-US/docs/Web/API/CryptoKey