Fixed #23607 -- Typo in docs/ref/contrib/staticfiles.txt.

Thanks Rolandde for the report.

docs/ref/contrib/staticfiles.txt

@@ -73,7 +73,7 @@ respectively. For example::
         def __init__(self, *args, **kwargs):
             kwargs['file_permissions_mode'] = 0o640
             kwargs['directory_permissions_mode'] = 0o760
-            super(CustomStaticFilesStorage, self).__init__(*args, **kwargs)
+            super(MyStaticFilesStorage, self).__init__(*args, **kwargs)
 
 Then set the :setting:`STATICFILES_STORAGE` setting to
 ``'path.to.MyStaticFilesStorage'``.