Typo.

src/ZODB/interfaces.py

@@ -703,7 +703,7 @@ class IStorage(Interface):
         Changes must be made permanent at this point.
 
         This call is ignored if the storage isn't participating in
-        two-phase commit or if it is commiting a different
+        two-phase commit or if it is committing a different
         transaction.  Failure of this method is extremely serious.
 
         The second argument is a call-back function that must be