feat(native): add is-utf8 to replacements

docs/modules/is-utf8.md

@@ -0,0 +1,38 @@
+---
+description: Native alternatives to the is-utf8 package for checking whether bytes are valid UTF-8
+---
+
+# Replacements for `is-utf8`
+
+Both Node.js and the web platform can check for valid UTF-8 without a dependency. The two options below return the same answer, so it is only a question of where the code runs.
+
+One difference to keep in mind: among control characters `is-utf8` accepts only tab, line feed and carriage return, and rejects the other thirty even though all of them are valid UTF-8. If you were relying on that to tell text from binary, keep the check explicit.
+
+## `buffer.isUtf8` (native, since Node.js v19.4.0 / v18.14.0)
+
+[`buffer.isUtf8`](https://nodejs.org/api/buffer.html#bufferisutf8input) takes a `Buffer`, `TypedArray` or `ArrayBuffer`.
+
+```ts
+import isUtf8 from 'is-utf8' // [!code --]
+import { isUtf8 } from 'node:buffer' // [!code ++]
+
+isUtf8(bytes)
+```
+
+## `TextDecoder` (native, browsers and Node.js)
+
+Elsewhere, decode with [`TextDecoder`](https://developer.mozilla.org/en-US/docs/Web/API/TextDecoder) and `fatal: true`, which throws on malformed input instead of substituting replacement characters.
+
+<!-- prettier-ignore -->
+```ts
+import isUtf8 from 'is-utf8' // [!code --]
+const decoder = new TextDecoder('utf-8', {fatal: true}) // [!code ++]
+const isUtf8 = (bytes) => { // [!code ++]
+  try { // [!code ++]
+    decoder.decode(bytes) // [!code ++]
+    return true // [!code ++]
+  } catch { // [!code ++]
+    return false // [!code ++]
+  } // [!code ++]
+} // [!code ++]
+```

manifests/native.json

@@ -1719,6 +1719,13 @@
         "compatKey": "api.btoa"
       }
     },
+    "buffer.isUtf8": {
+      "id": "buffer.isUtf8",
+      "type": "native",
+      "description": "Checks whether a buffer, typed array or array buffer contains valid UTF-8, including control characters such as NUL and ESC.",
+      "url": {"type": "node", "id": "api/buffer.html#bufferisutf8input"},
+      "nodeFeatureId": {"moduleName": "node:buffer", "exportName": "isUtf8"}
+    },
     "class_field_arrow_functions": {
       "id": "class_field_arrow_functions",
       "type": "native",
@@ -2919,6 +2926,12 @@
       "moduleName": "is-url-superb",
       "replacements": ["URL.canParse"]
     },
+    "is-utf8": {
+      "type": "module",
+      "moduleName": "is-utf8",
+      "replacements": ["buffer.isUtf8", "TextDecoder"],
+      "url": {"type": "e18e", "id": "is-utf8"}
+    },
     "isarray": {
       "type": "module",
       "moduleName": "isarray",