Fix Typo in google.maps.d.ts

googlemaps/google.maps.d.ts

@@ -353,7 +353,7 @@ declare module google.maps {
         setDraggable(flag: boolean): void;
         setIcon(icon: string|Icon|Symbol): void;
         setMap(map: Map|StreetViewPanorama): void;
-        getOpacity(opacity: number): void;
+        setOpacity(opacity: number): void;
         setOptions(options: MarkerOptions): void;
         setPlace(place: Place): void;
         setPosition(latlng: LatLng|LatLngLiteral): void;