update notes to talk about -X showrefcount
diff --git a/Misc/SpecialBuilds.txt b/Misc/SpecialBuilds.txt
index 646ac23..732cb00 100644
--- a/Misc/SpecialBuilds.txt
+++ b/Misc/SpecialBuilds.txt
@@ -13,12 +13,14 @@
------------
Turn on aggregate reference counting. This arranges that extern _Py_RefTotal
-hold a count of all references, the sum of ob_refcnt across all objects. In a
-debug-mode build, this is where the "8288" comes from in
+hold a count of all references, the sum of ob_refcnt across all objects.
+Passing ``-X showrefcount`` on the command line causes the interactive
+interpreter to print the reference count total as well the number of memory
+blocks allocated after each statement:
>>> 23
23
- [8288 refs]
+ [8288 refs, 14332 blocks]
>>>
Note that if this count increases when you're not storing away new objects,