Go to the Keyword List panel in the right column. In the Filter Keywords box, type "Ane" -- does that keyword show? If the count to the right of "Ane" is 0, then that keyword isn't assigned to any pics, and you can simply delete it. But if "Ane" is assigned to faces in pics, then you'll have to go to each pic in turn, go to Loupe view, and change each face that has "Ane" to "Anne". Then you can delete "Ane" from the Keyword List.