More helpful error message when a module isn't found in the modules list of "prune_configuration.cc".
I recently encountered an issue with a module name that was not found in the modules list for an out of date standard fcl in dune for one of the prototype experiments. The expression of this was a standard library exception.
%MSG-s StdLibException: Standard library exception caught in art map::at %MSG Art has completed and will exit with status 66.
I tracked the exception down to prune_configuration.cc:273, showing a module was left in our fcl that is no longer configured. The result is a "module_name" which is not found in the "modules" map, causing the exception. It would be helpful for art to report this back to the user. I request a more detailed output when a module_name is not found in modules, including the name of the module that was not found.