All 38 languages, with Dutch on a smaller pack

This release replaces the core language set with every supported language.
Dutch now ships a reduced pack that is about 48% smaller; the trade-off is
coverage of rare words by the speller and tagger.

More reliable corrections in rich text editors

Applying a fix is now more dependable in editors that manage their own
content. The engine tells the editor exactly which text it is replacing, and
deleting text now also works in editors that only respond to keyboard input.

Fidus Writer support works in more places

Fidus Writer is now detected in the Nextcloud app and in the WordPress
plugin, in addition to the standalone version.