How to I change the Interpolation Type in the Map Range node like the documentation says? According to the documentation, you should be able to change the Interpolation Type of a Map Range node. I am on 2.91.2 and don't see it. Is this a new feature that I don't yet have access to?

Secondly, is it possible to create my own interpolation curve using math nodes instead? I am trying to remap a value that doesn't progress from 0-1 linearly so that it does follow a more linear range in implementation.
Keep in mind this is all in the shader editor, not compositor.
Gracious thanks for any help at all.
Make sure you are on the shader editor. In 2.9.12  the interpolation options are there: