Backport r57105 and r57145 from the py3k branch: UTF-32 codecs.
diff --git a/Doc/library/codecs.rst b/Doc/library/codecs.rst
index e86999e..867fbae 100644
--- a/Doc/library/codecs.rst
+++ b/Doc/library/codecs.rst
@@ -1045,6 +1045,12 @@
| shift_jisx0213 | shiftjisx0213, sjisx0213, | Japanese |
| | s_jisx0213 | |
+-----------------+--------------------------------+--------------------------------+
+| utf_32 | U32, utf32 | all languages |
++-----------------+--------------------------------+--------------------------------+
+| utf_32_be | UTF-32BE | all languages |
++-----------------+--------------------------------+--------------------------------+
+| utf_32_le | UTF-32LE | all languages |
++-----------------+--------------------------------+--------------------------------+
| utf_16 | U16, utf16 | all languages |
+-----------------+--------------------------------+--------------------------------+
| utf_16_be | UTF-16BE | all languages (BMP only) |