Fix a nasty bug with typed subarrays

[KTibow]

If you have a typed subarray for whatever reason, like using pbf's readBytes, devalue currently stringifies the whole buffer as shown in this example:

import { parse, stringify } from "npm:devalue";

const buffer = new ArrayBuffer(100);
const view = new Uint8Array(buffer);
const subarray = view.subarray(0, 10);

console.log(subarray.length); // 10
console.log(parse(stringify(subarray)).length); // Incorrectly 100

This fixes that by calling .slice() first.