document scope need for parameter exploration

![image](https://user-images.githubusercontent.com/5268/183572002-35322649-d22f-4d88-8987-77bbb4b73d87.png)

[README.md ](https://github.com/proppy/rad-lab/blob/tuning/modules/silicon_design/README.md) should be updated to list scope required for running the [tuning](https://github.com/proppy/rad-lab/blob/tuning/modules/silicon_design/scripts/build/notebooks/xls/tuning.md) notebook.
