title: Typescript Pick type not mapping intellisense
body: <p>The Typescript <a href="https://www.typescriptlang.org/docs/handbook/advanced-types.html" rel="nofollow noreferrer">Pick type</a> is not mapping intellisense in vscode (or stackblitz). If <code>MyType</code> has a documented property, then you define a type as <code>Pick&lt;MyType, 'someProperty'&gt;</code>, then you mouseover <code>.someProperty</code> you won't see the documentation or if you right-click -> Go to Definition it won't find any. It will for <code>Partial&lt;MyType&gt;</code> though.</p>
  
  <p>I made workaround type <code>PickPartial&lt;T, K extends keyof T&gt;</code> and demonstration <a href="https://stackblitz.com/edit/typescript-pick-partial?file=index.ts" rel="nofollow noreferrer">here</a>. Is this a Typescript or vscode bug or how <code>Pick</code> should behave?</p>