Change constructor type for instanceOf expectation

It should result in an error.

Author: novemberborn

index.d.ts

@@ -5,15 +5,15 @@ export interface Subscribable {
 	}): void;
 }
 
-export type Constructor = (new (...args: any[]) => any);
+export type ErrorConstructor = new (...args: any[]) => Error;
 
 /** Specify one or more expectations the thrown error must satisfy. */
 export type ThrowsExpectation = {
 	/** The thrown error must have a code that equals the given string or number. */
 	code?: string | number;
 
 	/** The thrown error must be an instance of this constructor. */
-	instanceOf?: Constructor;
+	instanceOf?: ErrorConstructor;
 
 	/** The thrown error must be strictly equal to this value. */
 	is?: Error;