No bug - Archive completed Fluent migrations. rs=me DONTBUILD

--HG--
rename : python/l10n/tb_fluent_migrations/bug_1889422_fluent_migration_accounts_dtd.py => python/l10n/tb_fluent_migrations/completed/bug_1889422_fluent_migration_accounts_dtd.py
rename : python/l10n/tb_fluent_migrations/bug_1890267_attachment_context_menu.py => python/l10n/tb_fluent_migrations/completed/bug_1890267_attachment_context_menu.py

python/l10n/tb_fluent_migrations/completed/bug_1890267_attachment_context_menu.py

@@ -1,8 +1,8 @@
 # Any copyright is dedicated to the Public Domain.
 # http://creativecommons.org/publicdomain/zero/1.0/
 
-from fluent.migrate import COPY_PATTERN
-from fluent.migrate.helpers import transforms_from
+from fluent.migratetb import COPY_PATTERN
+from fluent.migratetb.helpers import transforms_from
 
 
 def migrate(ctx):