fit_kws's key "Color in plot_figure_for_fit functino

Tell us the versions of your environment (ensure you are running the latest):

- [ ] forest benchmarking version: 
- [ ] pyQuil version:  
- [ ] qvm version:
- [ ] quilc version: 


**Describe the bug**

A clear and concise description of what the bug is.


**Steps to reproduce the behavior**

1. run this 
2. get that
3. ...
4. See error


**Possible solutions**
