bpo-35649: update http client example (GH-11441) (GH-15930)

(cherry picked from commit 62cf6981425c6a6b136c5e2abef853364f535e9d)

Co-authored-by: Ashwin Ramaswami <aramaswamis@gmail.com>
diff --git a/Doc/library/http.client.rst b/Doc/library/http.client.rst
index 4e761cd..48bc35c 100644
--- a/Doc/library/http.client.rst
+++ b/Doc/library/http.client.rst
@@ -516,8 +516,11 @@
    >>> # The following example demonstrates reading data in chunks.
    >>> conn.request("GET", "/")
    >>> r1 = conn.getresponse()
-   >>> while not r1.closed:
-   ...     print(r1.read(200))  # 200 bytes
+   >>> while True:
+   ...     chunk = r1.read(200)  # 200 bytes
+   ...     if not chunk:
+   ...          break
+   ...     print(repr(chunk))
    b'<!doctype html>\n<!--[if"...
    ...
    >>> # Example of an invalid request