So some documents do treat housing as a human right: (UN declaration of human rights) Article 25. (1) Everyone has the right to a standard of living adequate for the health and well-being of himself and of his family, including food, clothing, housing and medical care and necessary social services, and the right to security in the event of unemployment, sickness, disability, widowhood, old age or other lack of livelihood in circumstances beyond his control. - https://www.un.org/en/documents/udhr/

Constitutions for the most part are not about describing human rights. They are about describing the method of governments - who is elected where and how, what authorities they have and so forth. There's usually some flowery preamble at the start about how awesome we all are in country -foo-, but the role of a constitution is generally to describe the structure of government.