Fixes #20470 Map.addHandler takes a newable type as second param. (#22577)

types/leaflet/index.d.ts

@@ -1322,7 +1322,7 @@ export class Map extends Evented {
     flyToBounds(bounds: LatLngBoundsExpression, options?: FitBoundsOptions): this;
 
     // Other methods
-    addHandler(name: string, HandlerClass: () => Handler): this; // HandlerClass is actually a constructor function, is this the right way?
+    addHandler(name: string, HandlerClass: typeof Handler): this; // Alternatively, HandlerClass: new(map: Map) => Handler
     remove(): this;
     createPane(name: string, container?: HTMLElement): HTMLElement;
     /**

types/leaflet/leaflet-tests.ts

@@ -368,7 +368,7 @@ map = map
 	.flyToBounds(latLngBounds, fitBoundsOptions)
 	.flyToBounds(latLngBoundsLiteral)
 	.flyToBounds(latLngBoundsLiteral, fitBoundsOptions)
-	// addHandler
+	.addHandler('Hello World', L.Handler)
 	.remove()
 	.whenReady(() => {})
 	.whenReady(() => {}, {});