Feature: Improve contrast between complete and incomplete icons
Feature: Improve contrast between complete and incomplete icons

Because:
* We've seen some reports about it being a little hard to tell whats complete and incomplete on the course page

This commit:
* Use a darker shade of gray for the the incomplete icon

TheOdinProject/theodinproject,TheOdinProject/theodinproject,TheOdinProject/theodinproject,TheOdinProject/theodinproject