Updating docs to change around the order of extern and

AP[RU]_DECLARE_DATA. If this is incorrect, please yell.
However, the vast majority of the code follows the convention
documented in this patch.
If this is in error, I will gladly back it out.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89324 13f79535-47bb-0310-9956-ffa450edef68