histedit: correct changeset IDs in online help

There is no '633536316234' revision in the example repository. It
should be 'c561b4e977df', according to the revisions in it and
explanation in help document.

hgext/histedit.py

@@ -28,7 +28,7 file open in your editor::
  pick 030b686bedc4 Add gamma
  pick 7c2fd3b9020c Add delta
 
- # Edit history between 633536316234 and 7c2fd3b9020c
+ # Edit history between c561b4e977df and 7c2fd3b9020c
  #
  # Commands:
  #  p, pick = use commit
@@ -47,7 +47,7 would reorganize the file to look like t
  pick c561b4e977df Add beta
  fold 7c2fd3b9020c Add delta
 
- # Edit history between 633536316234 and 7c2fd3b9020c
+ # Edit history between c561b4e977df and 7c2fd3b9020c
  #
  # Commands:
  #  p, pick = use commit