doc(bigquery): remove spurious comment
Artifact of copy and pasting.  The tableID comment isn't needed for
table listing.
@@ -28,7 +28,6 @@ import (
func listTables(w io.Writer, projectID, datasetID string) error {
// projectID := "my-project-id"
// datasetID := "mydataset"
- // tableID := "mytable"
ctx := context.Background()
client, err := bigquery.NewClient(ctx, projectID)
if err != nil {
