Support .d.ts

[syumai]

• Parse .d.ts and create alias for them
  • https://deno.land/std/manual.md

Patterns

• Compiler hint

// @deno-types="./vendor/https/deno.land/std/foo/bar.d.ts"
import * as bar from "./bar.js";

• Triple-slash reference in .js

/// <reference types="./vendor/https/deno.land/std/foo/bar.d.ts" />
export const bar = "bar";