Fix a doxygen syntax related to @brief at the beginning of the file.

Prefer @subsubsection over @section, the output with doxygen 1.9.1 is less aggressive.

Add the release date for 2.17

Add a new entry for 2.18

git-svn-id: https://svn.apache.org/repos/asf/httpd/apreq/trunk@1903735 13f79535-47bb-0310-9956-ffa450edef68
1 file changed