Aḥsanallāhu ilaykum, is the ḥadd of rajm for a muḥṣan zānī an example of the text being abrogated while the ruling remains? Jazākam Allāhu khayran

Yes. This is the well known example the scholars of usul al fiqh (the foundational principles of jurisprudence) give for naskh al tilawah with the ruling remaining, meaning the wording was lifted from the recited Quran while its ruling stayed in force. The reported wording (al shaykh wa al shaykhah idha zanaya farjumuhuma al battah) is no longer recited as Quran, yet the ruling of stoning the married person who commits zina remains established by the Sunnah and the consensus of the scholars. Umar ibn al Khattab (radiyallahu anhu) said on the minbar of the Messenger of Allah sallallahu alayhi wa sallam that Allah revealed to him the ayah of stoning, and that he feared a time would come when someone would say we do not find stoning in the Book of Allah and so go astray by abandoning an obligation Allah revealed (agreed upon).