fix ramsey_model syntax
@MichelJuillard Currently ramsey_model
accepts a list of symbols in the syntax and the RamseyModelStatement
accepts a symbol_list
but nothing is done with it. Furthermore, there's no reference to the symbol_list
form in the manual. Is there a reason you added support for symbol_list
to ramsey_model
in d945395a, e90859ba, and 17477ab0