add a replacement API for PyCObject, PyCapsule #5630

All stdlib modules with C-APIs now use this.

Patch by Larry Hastings
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index 201f490..8f68cf7 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -644,7 +644,7 @@
             def delx(self): del self.__x
             x = property(getx, setx, delx, "")
             check(x, size(h + '4Pi'))
-        # PyCObject
+        # PyCapsule
         # XXX
         # rangeiterator
         check(iter(range(1)), size(h + '4l'))