change role "name" -> "Definition", with field "symbol", as to not clash with VarT's field name
fix tests for Boolean to adapt to changing role name -> Definition
fix ListADT to adapt to changing role name -> Definition
fix MaybeADT to adapt to changing role name -> Definition
fix PairADT to adapt to changing role name -> Definition
fix TermADT to adapt to changing role name -> Definition
fix tests for Test::Util to adapt to changing role name -> Definition