fix#6418

This request fix  [window.open return
type](microsoft/TypeScript#6418) issue.

Author: YuichiNukiyama

baselines/dom.generated.d.ts

@@ -11977,7 +11977,7 @@ interface Window extends EventTarget, WindowTimers, WindowSessionStorage, Window
     msMatchMedia(mediaQuery: string): MediaQueryList;
     msRequestAnimationFrame(callback: FrameRequestCallback): number;
     msWriteProfilerMark(profilerMarkName: string): void;
-    open(url?: string, target?: string, features?: string, replace?: boolean): any;
+    open(url?: string, target?: string, features?: string, replace?: boolean): Window;
     postMessage(message: any, targetOrigin: string, ports?: any): void;
     print(): void;
     prompt(message?: string, _default?: string): string;

inputfiles/overridingTypes.json

@@ -295,5 +295,11 @@
         "interface": "IDBDatabase",
         "name": "version",
         "type": "number"
+    },
+    {
+        "kind": "method",
+        "interface": "Window",
+        "name": "open",
+        "signatures": ["open(url?: string, target?: string, features?: string, replace?: boolean): Window"]
     }
 ]