IntoIterator::into_iter(values) vs values.into_iter() in a Rust for loop

Later on I read somewhere that calling it with dot method does reborrowing but no reborrowing takes place when calling it with the fully qualified name, is that right?

Almost. Calling a method with path syntax still does reborrowing if the target type is known ahead of time to be a reference. But IntoIterator::intoiter() is a trait method - generic over Self, so it does not. Calling it with e.g. ::intoiter(values) will work.

If my understanding is right where in the docs is this being explained? I couldn't find it yet

Reborrowing isn't documented well enough, unfortunately.