Update Lib/http/client.py

Co-authored-by: Illia Volochii <illia.volochii@gmail.com>

Author: sethmlarson

Lib/http/client.py

@@ -977,7 +977,8 @@ def _wrap_ipv6(self, ip):
 
     def _tunnel(self):
         if _contains_disallowed_url_pchar_re.search(self._tunnel_host):
-            raise ValueError('Invalid header value %r' % (self._tunnel_host,))
+            raise ValueError('Tunnel host can't contain control characters %r'
+                             % (self._tunnel_host,))
         connect = b"CONNECT %s:%d %s\r\n" % (
             self._wrap_ipv6(self._tunnel_host.encode("idna")),
             self._tunnel_port,