A tenant is someone who occupies real property owned by someone else. A tenet is a central principle or belief. Both words descend from the Latin word tenere which means to hold. Think about that for a moment, and the logic behind the etymology should be clear. A tenant is someone who “holds” real property, and a tenet is an idea that someone holds.
Both tenant and tenet also have the same pronunciation, so an audience must use context to distinguish between the two words in spoken English. In written English, however, the difference in spelling (as well as the difference in context based in the difference in meaning) provides the distinction.
So respect the tenet about tenants by using the proper word to convey your intended meaning. More precise language produces more effective technical writing. And more effective technical writing provides a better presentation of both you and your brand.