Support @deno_types

[whinc]

the @deno_types directive don't work correctly in vscode type check. For example:
a.js

export const a = 100

a.d.ts

declare const a: boolean
export {a}

Variable a should has type boolean instead of number literal 100 in vscode type checker.

deno builtin type checker is correct when i run the program.

[justjavac]

WIP

[xcatliu]

Still report error after upgrade vscode deno plugin version to 1.24.0