Champ: Standardize Learner Hints

[felixwalberg]

Develop a convention/standard format for how we hint that learners need to make changes. Should these all be TODO comments in the code? Should it be mentioned in the narrative? Both? Whatever we decide, we will make sure it is consistent to avoid confusion.

[felixwalberg]

We plan to add another hint NPC to the combat level about replacing the buoy.tscn and add to the dialogue of the NPC in the sequence puzzle to include a hint about changing the animation for defeat.