Merge pull request #34 from github/use-html-element-tag-name-map

Add HTMLElementTagNameMap interface to TypeScript declaration file.

index.d.ts

@@ -19,4 +19,7 @@ declare global {
   interface Window {
     AutocompleteElement: typeof AutocompleteElement
   }
-}
+  interface HTMLElementTagNameMap {
+    'auto-complete': AutoCompleteElement
+  }
+}