Updated comment text

 - Legacy-Id: 15131

Author: levkowetz

ietf/utils/history.py

@@ -1,6 +1,6 @@
 def find_history_active_at(obj, time):
     """Assumes obj has a corresponding history model (e.g. obj could
-    be Person with a corresponding PersonHistory model), then either
+    be Document with a corresponding DocHistory model), then either
     returns the object itself if it was active at time, or the history
     object active at time, or None if time predates the object and its
     history (assuming history is complete).