Backport of r81088, plus the exposure of the previously undocumented

Backport of r81088, plus the exposure of the previously undocumented
*ReflectionKey functions. Apparently that was not backported.

Merged revisions 81088 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r81088 | brian.curtin | 2010-05-11 14:13:13 -0500 (Tue, 11 May 2010) | 13 lines

  #8575 - Update and reorganize some _winreg contents.

  I've removed the hopeful note about a future higher-level module since
  it's been in there for quite a long time and nothing of the sort has
  come up. There are a few places where markup was added to cross-reference
  other sections, and many of the external links have been removed and now
  point to newly created sections containing previously undocumented
  information.

  The Value Types section was created and it's contents were taken from
  a function-specific area, since it applies to more than just that
  function. It fits in better with the other newly documented constants.
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