[docs] Update docs for building from source (#26045)
[docs] Update docs for building from source (#26045)

The existing docs didn't work for me and these updates did. 🤷‍♀️ I selectively pulled this stuff out of the CI (which ideally would just be runnable locally).
ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray