Review doxygen warnings

Review doxygen warnings

We write doxygen comments but we do not verify them. So
quite some errors have crept in. Trying to reduce them
by reviewing the warnings output of doxygen and addressing
most of them.

Did generally ignore "The following parameter is not documented"
warnings (except those caused by typos). Fixing those will
require more work.

Usual errors fixed:
 - Wrong usage of @file
 - Wrong spellings of @param
 - Desync between function declaration and comment
   (usually param names)

Change-Id: I7a852eb5fafae3a0e85dd89ea6d4c91fcf2fab4e
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Arne Schwabe <arne-openvpn@rfc2549.org>
Message-Id: <20241227161648.3350-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg30256.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>