Add instructions that add collaborator content & generate the merge conflict

[lindsayplatt]

Make sure this appears in a user guide, too.

• The end of Step 9 Closing the loop should say the following: "Before you go on to the next section, your instructor will need to take an action. Ping them to get them to do it, and wait until after they have confirmed things are ready before you move on to the next section.". This is because the static version doesn't have a bot that will automatically simulate a collaborators action. The course contact must do it. For the guide, we need to create additional human-readable instructions for doing this GH action.
• The beginning of Step 11 Add two new sections of the story is where we have the merge conflict inserted. You should add "Ping your instructor and let them know that you have arrived at this step. There is something that they need to do." to the top of the list. This is where the contact needs to initiate the merge conflict by recreating this GH action. This should go in a course contact guide somewhere. I believe it is just deleting the hyperlink for the word "reservoir"