Adds VarDate and SafeArray<T> as pseudonominal types to lib.d.ts (#18566)

* SafeArray<T>; stronger typing for VarDate, and for VBArray and Enumerator constructors

* Add overload to Enumerator based on Item method

* Add return type to Enumerator constructor

Author: zspitz

src/lib/scripthost.d.ts

@@ -201,10 +201,18 @@ declare var WScript: {
     Sleep(intTime: number): void;
 };
 
+/**
+ * Represents an Automation SAFEARRAY
+ */
+declare class SafeArray<T = any> {
+    private constructor();
+    private SafeArray_typekey: SafeArray<T>;
+}
+
 /**
  * Allows enumerating over a COM collection, which may not have indexed item access.
  */
-interface Enumerator<T> {
+interface Enumerator<T = any> {
     /**
      * Returns true if the current item is the last one in the collection, or the collection is empty,
      * or the current item is undefined.
@@ -230,16 +238,17 @@ interface Enumerator<T> {
 }
 
 interface EnumeratorConstructor {
-    new <T>(collection: any): Enumerator<T>;
-    new (collection: any): Enumerator<any>;
+    new <T = any>(safearray: SafeArray<T>): Enumerator<T>;
+    new <T = any>(collection: { Item(index: any): T }): Enumerator<T>;
+    new <T = any>(collection: any): Enumerator<T>;
 }
 
 declare var Enumerator: EnumeratorConstructor;
 
 /**
  * Enables reading from a COM safe array, which might have an alternate lower bound, or multiple dimensions.
  */
-interface VBArray<T> {
+interface VBArray<T = any> {
     /**
      * Returns the number of dimensions (1-based).
      */
@@ -271,16 +280,18 @@ interface VBArray<T> {
 }
 
 interface VBArrayConstructor {
-    new <T>(safeArray: any): VBArray<T>;
-    new (safeArray: any): VBArray<any>;
+    new <T = any>(safeArray: SafeArray<T>): VBArray<T>;
 }
 
 declare var VBArray: VBArrayConstructor;
 
 /**
  * Automation date (VT_DATE)
  */
-interface VarDate { }
+declare class VarDate {
+    private constructor();
+    private VarDate_typekey: VarDate;
+}
 
 interface DateConstructor {
     new (vd: VarDate): Date;