Add defaults for params and constants in python-xlib (#9642)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

stubs/python-xlib/@tests/stubtest_allowlist.txt

@@ -22,3 +22,4 @@ Xlib.protocol.rq.Struct.__getattr__
 
 # Iteration variable that bleeds into the global scope
 Xlib.protocol.rq.c
+Xlib.protocol.rq.size

stubs/python-xlib/@tests/stubtest_allowlist_win32.txt

@@ -1,3 +0,0 @@
-# failed to import, ModuleNotFoundError: No module named 'fcntl'
-# https://github.com/python-xlib/python-xlib/pull/217
-Xlib.support.unix_connect