Add d.ts file to npm publish

Author: pomber

packages/mdx/package.json

@@ -2,7 +2,8 @@
   "name": "@code-hike/mdx",
   "version": "0.7.2",
   "files": [
-    "dist"
+    "dist",
+    "components.d.ts"
   ],
   "main": "./dist/index.cjs.js",
   "module": "./dist/index.esm.mjs",