Edited the web.run_app declaration. (#6401)

* Edited the web.run_app declaration.

The run_app function takes the "sock" parameter which
can be iterable as well.

* Updated CONTRIBUTORS.txt.

* Added description to CHANGES.

* Use TypingIterable instead of Iterable.

CHANGES/6401.doc

@@ -0,0 +1 @@
+Edited the web.run_app declaration.

CONTRIBUTORS.txt

@@ -234,6 +234,7 @@ Navid Sheikhol
 Nicolas Braem
 Nikolay Kim
 Nikolay Novik
+Nikolay Tiunov
 Nándor Mátravölgyi
 Oisin Aylward
 Olaf Conradi

aiohttp/web.py

@@ -289,7 +289,7 @@ async def _run_app(
     host: Optional[Union[str, HostSequence]] = None,
     port: Optional[int] = None,
     path: Optional[str] = None,
-    sock: Optional[socket.socket] = None,
+    sock: Optional[Union[socket.socket, TypingIterable[socket.socket]]] = None,
     shutdown_timeout: float = 60.0,
     keepalive_timeout: float = 75.0,
     ssl_context: Optional[SSLContext] = None,
@@ -463,7 +463,7 @@ def run_app(
     host: Optional[Union[str, HostSequence]] = None,
     port: Optional[int] = None,
     path: Optional[str] = None,
-    sock: Optional[socket.socket] = None,
+    sock: Optional[Union[socket.socket, TypingIterable[socket.socket]]] = None,
     shutdown_timeout: float = 60.0,
     keepalive_timeout: float = 75.0,
     ssl_context: Optional[SSLContext] = None,