feat(library): ✨ support built-in typescript definition

add typescript definition which has stricter type than `@types/void-elements`

fix pugjs#23

package.json

@@ -3,6 +3,7 @@
  "version": "3.1.0",
  "description": "Array of \"void elements\" defined by the HTML specification.",
  "main": "index.js",
+ "typings": "types.d.ts",
  "jsnext:main": "index.es.js",
  "module": "index.es.js",
  "exports": {
@@ -23,7 +24,8 @@
  ],
  "files": [
  "index.js",
- "index.es.js"
+ "index.es.js",
+ "types.d.ts"
  ],
  "repository": "pugjs/void-elements",
  "author": "hemanth.hm",

types.d.ts

@@ -0,0 +1,5 @@
+declare type VoidElementKeys = 'area' | 'base' | 'br' | 'col' | 'embed' | 'hr' | 'img' | 'input' | 'link' | 'meta' | 'param' | 'source' | 'track' | 'wbr';
+
+declare const voidElements: Record<VoidElementKeys, true>;
+
+export default voidElements;