Ramban on Chayyei Sara: The Burial of Sarah in Eretz Yisrael - the Location of the Cave of Makhpela

In the story of Avraham buying the burial plot for Sarah in Hebron, why does one of the verses state that Hebron is located in the Land of Canaan?

Ramban notes that some view this detail as emphasizing that the forefathers were buried in Eretz Yisrael - a place ofgreater kedusha than outside Israel. In Ramban's opinion, though, the Torah is not contrasting Canaan to "Chutz La'Aretz" (outside of the Land of Israel), but rather highlighting that Avraham was buying a plot in Canaan as opposed to the Land of Pelishtim. Avraham chooses a place that is in the hills -  the heartland of the future Land of Israel.