fix namespace for promise

docs/httplug/index.md

@@ -9,14 +9,14 @@ In both cases, the `Http\Client\HttpClient` provides a `sendRequest` method to s
 and returns a PSR-7 `ResponseInterface`or throws an exception that implements `Http\Client\Exception`.
 
 There is also the `Http\Client\HttpAsyncClient` which provides the `sendAsyncRequest` method to send
-a request asynchronously and returns a `Http\Client\Promise`.
+a request asynchronously and returns a `Http\Promise\Promise`.
 
 The promise allows to specify handlers for a PSR-7 `ResponseInterface`
 or an exception that implements `Http\Client\Exception`.
 
 
 <p class="text-warning">
-    Contract for the `Http\Client\Promise` is temporary until
+    Contract for the `Http\Promise\Promise` is temporary until
     [PSR is released](https://groups.google.com/forum/?fromgroups#!topic/php-fig/wzQWpLvNSjs).
     Once it is out, we will use this PSR in the main client and deprecate the old contract.
 </p>
@@ -37,7 +37,7 @@ There are two kind of implementations:
  - [php-http/client-implementation](https://packagist.org/providers/php-http/client-implementation):
  the synchronous implementation that waits for the response / error before returning from the `sendRequest` method.
  - [php-http/async-client-implementation](https://packagist.org/providers/php-http/async-client-implementation):
- the asynchronous implementation that immediately returns a `Http\Client\Promise`,
+ the asynchronous implementation that immediately returns a `Http\Promise\Promise`,
  allowing to send several requests in parallel and handling responses later.
 
 Check links above for the full list of implementations.