Spelling fixes supplied by Rob W. W. Hooft. All these are fixes in either
comments, docstrings or error messages. I fixed two minor things in
test_winreg.py ("didn't" -> "Didn't" and "Didnt" -> "Didn't").

There is a minor style issue involved: Guido seems to have preferred English
grammar (behaviour, honour) in a couple places. This patch changes that to
American, which is the more prominent style in the source. I prefer English
myself, so if English is preferred, I'd be happy to supply a patch myself ;)
diff --git a/Objects/object.c b/Objects/object.c
index 64d8a82..ef3455e 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -337,7 +337,7 @@
 
 PyObject *_PyCompareState_Key;
 
-/* _PyCompareState_nesting is incremented beforing call compare (for
+/* _PyCompareState_nesting is incremented before calling compare (for
    some types) and decremented on exit.  If the count exceeds the
    nesting limit, enable code to detect circular data structures.
 */