[NFC] Rename tutorial section "Data Frame" -> "Dataframe"
[NFC] Rename tutorial section "Data Frame" -> "Dataframe"

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