Deliver shell completion query replies

execute.go

@@ -30,6 +30,9 @@ func (a *App) Execute(ctx context.Context, args []string, streams Streams) Outco
 		err := errors.New("invocation context must not be nil")
 		return current.finalize(Failure(err.Error()).WithCause(err), nil, false)
 	}
+	if current.snapshot != nil && current.snapshot.completion && len(args) > 0 && args[0] == internalcobra.CompletionQueryToken {
+		return current.complete(args[1:])
+	}
 	routedSnapshot := current.snapshot
 	current.route = resolveEnteredRoute(args, routedSnapshot)
 	current.recordRouteEvents()