Fix link to servant-swagger haddocks (#1670)

Author: Taneb

servant-swagger/README.md

@@ -24,7 +24,7 @@ Generated Swagger specification then can be used for many things such as
 
 ### Usage
 
-Please refer to [haddock documentation](http://hackage.haskell.org/package/servant/servant-swagger).
+Please refer to [haddock documentation](http://hackage.haskell.org/package/servant-swagger).
 
 Some examples can be found in [`example/` directory](/example).