docs(setup/install): fix inconsistent numbering (#838)
docs(setup/install): fix inconsistent numbering (#838)

On the [install page](https://www.spinnaker.io/setup/install/), "Choose an environment" is 2.
However, [the environment page](https://www.spinnaker.io/setup/install/environment/) shows it as 3.
Likewise, "Choose Cloud Providers" is 3 on the [install page](https://www.spinnaker.io/setup/install/), but [the providers page](https://www.spinnaker.io/setup/install/providers/) shows 2.
This PR makes the numbering consistent.
ttomsu/spinnaker.github.io,ttomsu/spinnaker.github.io,spinnaker/spinnaker.github.io,spinnaker/spinnaker.github.io,ttomsu/spinnaker.github.io,spinnaker/spinnaker.github.io