Fix instructions about tag filtering
Fix instructions about tag filtering

Since afc8edf724c58553f48574ac5fe3484cbc1c7c76,
that command does not produce a usable output any more.

Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2