Fix a few more memory leaks

Document more info about the benefits of configuring without
pymalloc when running valgrind
diff --git a/Python/modsupport.c b/Python/modsupport.c
index 197d99b..fbfb48d 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -82,6 +82,7 @@
 			}
 			Py_DECREF(v);
 		}
+		Py_DECREF(n);
 	}
 	if (doc != NULL) {
 		v = PyString_FromString(doc);