configparser doc: Properly label ConfigParser attributes (GH-9930)

diff --git a/Doc/library/configparser.rst b/Doc/library/configparser.rst
index 0ae466e..47d6172 100644
--- a/Doc/library/configparser.rst
+++ b/Doc/library/configparser.rst
@@ -663,7 +663,7 @@
 these parser attributes.  The defaults are defined on the classes, so they may
 be overridden by subclasses or by attribute assignment.
 
-.. attribute:: BOOLEAN_STATES
+.. attribute:: ConfigParser.BOOLEAN_STATES
 
   By default when using :meth:`~ConfigParser.getboolean`, config parsers
   consider the following values ``True``: ``'1'``, ``'yes'``, ``'true'``,
@@ -686,7 +686,7 @@
   Other typical Boolean pairs include ``accept``/``reject`` or
   ``enabled``/``disabled``.
 
-.. method:: optionxform(option)
+.. method:: ConfigParser.optionxform(option)
 
   This method transforms option names on every read, get, or set
   operation.  The default converts the name to lowercase.  This also
@@ -717,7 +717,7 @@
      >>> list(custom['Section2'].keys())
      ['AnotherKey']
 
-.. attribute:: SECTCRE
+.. attribute:: ConfigParser.SECTCRE
 
   A compiled regular expression used to parse section headers.  The default
   matches ``[section]`` to the name ``"section"``.  Whitespace is considered