clean up a lot of doxygen errors and warnings (issue #5522)

ast_expr2f.c

codecs/log2comp.h

include/asterisk/adsi.h

include/asterisk/callerid.h

include/asterisk/cdr.h

include/asterisk/channel.h

include/asterisk/config.h

include/asterisk/devicestate.h

include/asterisk/doxyref.h

include/asterisk/enum.h

include/asterisk/file.h

include/asterisk/frame.h

include/asterisk/manager.h

include/asterisk/module.h

include/asterisk/pbx.h

include/asterisk/plc.h

include/asterisk/strings.h

include/asterisk/tdd.h

manager.c

pbx.c