cmds / lib: Fix more static checker findings

Fix more errors and warnings produced by "make check" as reported by CI and a pyright upgrade.
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/App.py

@@ -180,8 +180,8 @@ class App:  # export
 
             class NoopCompleter(BaseCompleter):
 
-                def __call__(self, **kwargs):
-                    return ()
+                def __call__(self, *args, **kwargs):
+                    return None
 
             import argcomplete
 
@@ -224,6 +224,7 @@ class App:  # export
                     NOTICE,
                     f'Writing profile statistics to {self.__args.write_profile}'
                 )
+                assert self.__args.write_profile is not None, 'args.write_profile'
                 pr.dump_stats(self.__args.write_profile)
 
         if exit_status: