textapi: put a label on sequence items
# Feature Request
## Description
see title
this is in common with recent improvements in [TextAPI](https://subugoe.pages.gwdg.de/emo/text-api/page/specs/#sequence-object) and TIDO.
Source: https://chat.gwdg.de/group/Ahiqar?msg=ASpZprZEfK92EXuhR
## User Story
As a smart front end developer I want to prevent a massive number of requests in order to improve the performance ot the application.
/cc [Michelle Weidling](https://gitlab.gwdg.de/mrodzis)
issue