help/config: note 64-bit Windows registry key used with 32-bit Python Before this patch the only place that documented the use of a different registry key was on the wiki page for installing on Windows from sources, while most users will use a pre-packaged installer and the supplied help files. This patch documents in the supplied help files that an alternate registry key is used for the installation/system configuration file when using 32-bit Python on a 64-bit Windows.