Adds every message of MishkaGervaz's .pot files to the core's .pot file of the same domain.
A host sets config :mishka_gervaz, :gettext_backend, MishkaCmsCore.Gettext, so MishkaGervaz's
own words are translated from the core's .po files. mix gettext.extract finds only the core's
own messages, so run this after it and merge the templates into the .po files again:
mix gettext.extract --merge --no-fuzzy
mix mishka_cms_core.gettext.gervaz
mix mishka_cms_core.gettext.extensions
mix gettext.merge priv/gettext --no-fuzzyA message the core writes too is left as it is. Any other keeps its references into MishkaGervaz,
beside those of the extensions, which the project's :excluded_refs_from_purging keeps through
the next mix gettext.extract, so mix gettext.extract --check-up-to-date still passes. A
message neither MishkaGervaz nor an extension has any longer is removed. See
Mix.MishkaCmsCore.GettextTemplates.