chainedToPrev / chainedToNext still present and should be removed

[grahambell]

These elements are still present in some places, such as the UKIRT libraries, despite having been removed from the schema in 508059e. (The outcome is that if you make an observation based on the UKIRT UFTI library, for example, it doesn't validate.)

[timj]

Was it removed because the corresponding feature was removed from UFTI or because of an error? (I have to say that I don't think chainedToPrev was ever used by the OMP even if it was used in the previous ORAC system).

[grahambell]

That commit mentions 4450fbd which removed them from the OT saying "they haven't been used in years". I don't see chainedTo in the OMP or QT except for in test files. Saving my observation made the OT rewrite the XML without these elements and then it validated, but they still ought to be removed from the libraries.

[timj]

Agreed. I've updated the title of this issue to make that clearer (I initially thought the issue related to an error in the schema).