doxygen: fix warnings
There are tons of warnings that I don't understand. For instance:
doxygen: /Users/akim/src/lrde/2/vcsn/dyn/algos.hh:150: warning: argument 'p' of command @param is not found in the argument list of vcsn::dyn::cotrie(const polynomial &poly)
doxygen: /Users/akim/src/lrde/2/vcsn/dyn/algos.hh:154: warning: The following parameters of vcsn::dyn::cotrie(const polynomial &poly) are not documented:
parameter 'poly'
but:
150 /// A reversed trie-like automaton (multiple initial states,
151 /// single final state) automaton to accept \a p.
152 ///
153 /// \param p the polynomial that describes the (finite) series
154 automaton cotrie(const polynomial& p);
Please, fix as many warnings as possible.