Register BayesianFilter, update message keys

https://gerrit.wikimedia.org/r/#/c/85655/2/CategoryTree.i18n.php,unified
https://gerrit.wikimedia.org/r/#/c/86005/2/SemanticWatchlist.i18n.php,unified

Change-Id: I4a93dd674f94dc2fbd4638ae345015e3fa5fee86