[ntuple, doc] Better define 'offset' in format spec (NFC)
[ntuple, doc] Better define 'offset' in format spec (NFC)

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root