PEP 572: pass mandatory bufsize sock.recv() argument (#733)

* pass mandatory bufsize sock.recv() argument

* remove unnecessary space

pep-0572.rst

@@ -571,7 +571,7 @@ an ``if`` or ``while`` statement::
         print("Fallback found:", match.group(0))
 
     # Reading socket data until an empty string is returned
-    while data := sock.recv():
+    while data := sock.recv(8192):
         print("Received data:", data)
 
 Particularly with the ``while`` loop, this can remove the need to have an