test: Add property-based tests

Following the discussion started on #79. I'm opening this PR as an opened question and suggestion to better cover the library and its edge-cases.

First, what is property-based testing?

It's a technic coming from functional world and aiming to help devs into detecting edge cases without having them to think of them too much.

Why, property-based testing?

Well, in order to reduce the risks of bugs and potentially regressions on key libraries.

Could it found problems?

Well, probably. I tried another property but I'm not sure whether or not the failure is considered as ok or not. As such I'm not sure of what to expect from truncate so I was not able to make a decision.

```js
it('produces strings with at most <truncate> characters', () => {
  fc.assert(
    fc.property(
      fc.anything({
        withBigInt: true,
        withBoxedValues: true,
        withDate: true,
        withMap: true,
        withNullPrototype: true,
        withObjectString: true,
        withSet: true,
        withSparseArray: true,
        withTypedArray: true,
        withUnicodeString: true,
      }),
      fc.nat(),
      (source, truncate) => {
        const output = inspect(source, { truncate })
        expect(output).to.have.lengthOf.at.most(truncate)
      }
    )
  )
})
```

Who am I?

I'm the author of fast-check, the library added by this PR. It's the leading property-based testing library today.

package.json

@@ -115,6 +115,7 @@
     "eslint-config-strict": "^14.0.1",
     "eslint-plugin-filenames": "^1.3.2",
     "eslint-plugin-prettier": "^3.3.1",
+    "fast-check": "^3.19.0",
     "husky": "^4.3.8",
     "mocha": "^10.2.0",
     "nyc": "^15.1.0",

test/property.js

@@ -0,0 +1,28 @@
+import inspect from '../lib/index.js'
+import { expect } from 'chai'
+import fc from 'fast-check'
+
+describe('property', () => {
+  it('produces valid UTF-16 strings whatever the source', () => {
+    fc.assert(
+      fc.property(
+        fc.anything({
+          withBigInt: true,
+          withBoxedValues: true,
+          withDate: true,
+          withMap: true,
+          withNullPrototype: true,
+          withObjectString: true,
+          withSet: true,
+          withSparseArray: true,
+          withTypedArray: true,
+          withUnicodeString: true,
+        }),
+        fc.option(fc.nat(), { nil: undefined }),
+        (source, truncate) => {
+          expect(() => encodeURI(inspect(source, { truncate }))).not.to.throw()
+        }
+      )
+    )
+  })
+})