feat: add a bit of a clearer program output message

bin/cpp_engine.rb

@@ -64,7 +64,9 @@ $core.add_artefact_engine do |engine|
         a.parent_artefact :executable, match
 
         a.add_step do
+            print "\n\nPROGRAM OUTPUT FOR #{match}:\n"
             print `./#{@target.sub(/\.[^.\/]*\Z/, '')}`
+            print "\n\n"
         end
     end
 end