Fix type returned by end() (#85)

Author: kibertoad

index.d.ts

@@ -97,7 +97,7 @@ declare namespace LightMyRequest {
     payload: (payload: InjectPayload) => Chain
     query: (query: object) => Chain
     cookies: (query: object) => Chain
-    end: (callback?: CallbackFunc) => Chain | Promise<Response>
+    end: (callback?: CallbackFunc) => Promise<Response>
   }
 }
 

test/index.test-d.ts

@@ -72,6 +72,7 @@ inject(dispatch)
   })
 
 expectType<Chain>(inject(dispatch))
+expectType<Promise<Response>>(inject(dispatch).end())
 expectType<Chain>(inject(dispatch, { method: 'get', url: '/' }))
 // @ts-ignore tsd supports top-level await, but normal ts does not so ignore
 expectType<Response>(await inject(dispatch, { method: 'get', url: '/' }))