Add optional docstrings to getset descriptors.  Fortunately, there's
no backwards compatibility to worry about, so I just pushed the
'closure' struct member to the back -- it's never used in the current
code base (I may eliminate it, but that's more work because the getter
and setter signatures would have to change.)

As examples, I added actual docstrings to the getset attributes of a
few types: file.closed, xxsubtype.spamdict.state.
diff --git a/Objects/methodobject.c b/Objects/methodobject.c
index 5fe9178..e0968af 100644
--- a/Objects/methodobject.c
+++ b/Objects/methodobject.c
@@ -159,7 +159,7 @@
 	return self;
 }
 
-static struct getsetlist meth_getsets [] = {
+static PyGetSetDef meth_getsets [] = {
 	{"__doc__",  (getter)meth_get__doc__,  NULL, NULL},
 	{"__name__", (getter)meth_get__name__, NULL, NULL},
 	{"__self__", (getter)meth_get__self__, NULL, NULL},