Remove unneeded xo rule

Author: wooorm

package.json

@@ -102,9 +102,6 @@
         }
       }
     ],
-    "prettier": true,
-    "rules": {
-      "n/file-extension-in-import": "off"
-    }
+    "prettier": true
   }
 }

test/core.js

@@ -11,6 +11,7 @@ test('xastscript', async function (t) {
     'should expose the public api (`/jsx-runtime`)',
     async function () {
       assert.deepEqual(
+        // eslint-disable-next-line n/file-extension-in-import -- ESLint is wrong.
         Object.keys(await import('xastscript/jsx-runtime')).sort(),
         ['Fragment', 'jsx', 'jsxs']
       )
@@ -21,6 +22,7 @@ test('xastscript', async function (t) {
     'should expose the public api (`/jsx-dev-runtime`)',
     async function () {
       assert.deepEqual(
+        // eslint-disable-next-line n/file-extension-in-import -- ESLint is wrong.
         Object.keys(await import('xastscript/jsx-dev-runtime')).sort(),
         ['Fragment', 'jsxDEV']
       )