Small errors on sudo make doc following a pull of the latest version.

[f5vmr]

When making a pull of the latest svxlink to my node I noticed the following announcements that may or may not be important.
at ### sudo make doc :
warning: Tag 'SHOW_DIRECTORIES' at line 519 of file '/home/pi/svxlink/src/build/doc/doxygen.async' has become obsolete.
To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: Tag 'COLS_IN_ALPHA_INDEX' at line 800 of file '/home/pi/svxlink/src/build/doc/doxygen.async' has become obsolete.
To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: Tag 'PERL_PATH' at line 1511 of file '/home/pi/svxlink/src/build/doc/doxygen.async' has become obsolete.
To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: Tag 'MSCGEN_PATH' at line 1532 of file '/home/pi/svxlink/src/build/doc/doxygen.async' has become obsolete.
To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: doxygen no longer ships with the FreeSans font.
You may want to clear or change DOT_FONTNAME.
Otherwise you run the risk that the wrong font is being used for dot generated graphs.

Generating docs for compound Async::StateMachine...
/home/pi/svxlink/src/build/include/AsyncStateMachine.h:219: warning: Found unknown command '@retrun'
/home/pi/svxlink/src/build/include/AsyncStateMachine.h:219: warning: Found unknown command '@retrun'
/home/pi/svxlink/src/build/include/AsyncStateMachine.h:227: warning: *argument 'A' of command @param is not found in the argument list of Async::StateMachine< ContextT, StateTopT >::setState(NewStateT state=new NewStateT)
/home/pi/svxlink/src/build/include/AsyncStateMachine.h:241: warning: The following parameter of Async::StateMachine::setState(NewStateT *state=new NewStateT) is not documented:
parameter 'state'
Generating docs for compound Async::StateBase...
/home/pi/svxlink/src/build/include/AsyncStateMachine.h:456: warning: Found unknown command '@Bief'

**Hope that is of use.

Chris G4NAB.**

[f5vmr]

Still error reported :
svxlink/src/build/include/AsyncStateMachine.h:219: warning: Found unknown command '@retrun'

Should this be '@return'?