Update lib.d.ts with this parameters for event handlers

[sandersn]

Expected:

Intellisense from this

// @filename: lib.d.ts
onclick: (this: this, ev: MouseEvent) => any;
// @filename: test.ts
document.documentElement.onclick = function () {
    this./**/
}

Actual:
No intellisense from this:

onclick: (ev: MouseEvent) => any;

[sandersn]

microsoft/TypeScript-DOM-lib-generator#126 will address this.

[sandersn]

#9401 fixes this.