Fix two further doc build warnings.

Doc/library/stdtypes.rst

@@ -469,8 +469,9 @@ the iteration methods.
 One method needs to be defined for container objects to provide iteration
 support:
 
+.. XXX duplicated in reference/datamodel!
 
-.. method:: object.__iter__()
+.. method:: container.__iter__()
 
    Return an iterator object.  The object is required to support the iterator
    protocol described below.  If a container supports different types of

Doc/using/cmdline.rst

@@ -441,10 +441,10 @@ These environment variables influence Python's behavior.
 
 
 Debug-mode variables
---------------------
+~~~~~~~~~~~~~~~~~~~~
 
 Setting these variables only has an effect in a debug build of Python, that is,
-if Python was configured with the :opt:`--with-pydebug` build option.
+if Python was configured with the :option:`--with-pydebug` build option.
 
 .. envvar:: PYTHONTHREADDEBUG