Use an article instead of a for HTTP (#2)

* Use an article instead of a for HTTP

* One more replace of 'a HTTP' -> 'an HTTP'

Author: bocharsky-bw

README.md

@@ -4,11 +4,11 @@ PSR Http Client
 This repository holds all interfaces/classes/traits related to
 [PSR-18](http://www.php-fig.org/psr/psr-18/).
 
-Note that this is not a HTTP client implementation of its own. It is merely an
-interface that describes a HTTP client. See 
+Note that this is not an HTTP client implementation of its own. It is merely an
+interface that describes an HTTP client. See 
 [the specification](https://github.com/php-fig/fig-standards/blob/master/proposed/http-client/http-client.md)
 for more details.
 
 You can find implementations of the specification by looking for packages providing 
 the [psr/simple-cache-implementation](https://packagist.org/providers/psr/http-client-implementation)
-virtual package.
+virtual package.

src/ClientInterface.php

@@ -10,7 +10,7 @@ interface ClientInterface
     /**
      * Sends a PSR-7 request and returns a PSR-7 response.
      *
-     * Every technically correct HTTP response MUST be returned as is, even if it represents a HTTP
+     * Every technically correct HTTP response MUST be returned as is, even if it represents an HTTP
      * error response or a redirect instruction. The only special case is 1xx responses, which MUST
      * be assembled in the HTTP client.
      *
@@ -28,4 +28,4 @@ interface ClientInterface
      * @throws \Psr\Http\Client\Exception If an error happens during processing the request.
      */
     public function sendRequest(RequestInterface $request): ResponseInterface;
-}
+}