doc: fix libcoap removal commit in LOSTANDFOUND.md
doc: fix libcoap removal commit in LOSTANDFOUND.md

With PR RIOT-OS#17163 for removing `libcoap`, the file `LOSTANDFOUND.md` was updated to reference the commit for removing `libcoap`. The reference was not defined at the end of the file.
miri64/RIOT,ant9000/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,kaspar030/RIOT,miri64/RIOT,OlegHahm/RIOT,jasonatran/RIOT,kYc0o/RIOT,OlegHahm/RIOT,miri64/RIOT,kYc0o/RIOT,ant9000/RIOT,OlegHahm/RIOT,ant9000/RIOT,kaspar030/RIOT,jasonatran/RIOT,OlegHahm/RIOT,ant9000/RIOT,kYc0o/RIOT,kYc0o/RIOT,kYc0o/RIOT,miri64/RIOT,kaspar030/RIOT,jasonatran/RIOT,ant9000/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,miri64/RIOT,kaspar030/RIOT,RIOT-OS/RIOT