Restore the number of rows shown on Special:Watchlist

This reverts the result of Iada3a93762dd25fdaf35fb707304abc40bd4a5b1.
It used a param which was added to function doHeader in
I495d19258205d8713a19aa934a7657aecbe240d4.
It reused the old message to reduce translation interaction.

Bug: 62017
Change-Id: Ie722c509a6ad1346b1624abee778f4cbdc79d457
Merge "Restore the number of rows shown on Special:Watchlist"