Update the negated volume intro text

Author: dwhswenson

paths_cli/wizard/volumes.py

@@ -78,7 +78,8 @@ def _binary_func_volume(wizard, context, op):
 NEGATED_VOLUME_PLUGIN = WizardObjectPlugin(
     name='Complement of a volume (not in given volume)',
     category='volume',
-    intro="This volume will be everything not in the subvolume.",
+    intro=("This volume will be everything not in the input volume, which "
+           "you will define now."),
     builder=lambda wizard, context: ~VOLUMES_PLUGIN(
         wizard, volume_set_context(wizard, context, None)
     ),

paths_cli/wizard/wizard.py

@@ -79,7 +79,6 @@ def _speak(self, content, preface):
     @get_object
     def ask(self, question, options=None, default=None, helper=None,
             autohelp=False):
-        # TODO: if helper is None, create a default helper
         if helper is None:
             helper = Helper(None)
         if isinstance(helper, str):