Fix up type

Author: Luca Forstner

packages/nextjs/src/index.types.ts

@@ -33,4 +33,4 @@ export declare function getSentryRelease(fallback?: string): string | undefined;
 export declare function withSentryAPI<H extends (...args: any[]) => any>(
   handler: H,
   parameterizedRoute: string,
-): (...args: Parameters<H>) => Promise<ReturnType<H>>;
+): (...args: Parameters<H>) => ReturnType<H> extends Promise<unknown> ? ReturnType<H> : Promise<ReturnType<H>>;