Make all _connect arguments keyword-only

This gives us greater flexibility to reorder things or add things in the
future without breaking backwards compatibility.

Author: godlygeek

Lib/pdb.py

@@ -3263,7 +3263,7 @@ def complete(self, text, state):
             return None
 
 
-def _connect(host, port, frame, commands, version, signal_raising_thread):
+def _connect(*, host, port, frame, commands, version, signal_raising_thread):
     with closing(socket.create_connection((host, port))) as conn:
         sockfile = conn.makefile("rwb")