fix hw6 typo

assignments/hw6.md

@@ -56,7 +56,7 @@ You should expect that you may need to substantially revise your base game desig
 * **Update domain analysis:** Extend your domain model, system sequence diagram, and behavior contracts in `domain-model.pdf`, `system-sequence-diagram.pdf`, `contract.pdf` to include the new concept of god cards in the game. To keep things simple, you do not need to show all cards, but it is sufficient to just include the god card *Demeter* as a single concrete example in your design documents. For the contract you can assume that *the active player has the Demeter card* and the opposing player has no card.
 * **New justification for extension mechanisms:** Explain in about one paragraph how you redesigned your game to be extensible. In addition, as in Deliverable 5 and 6 of Homework 3, provide a justification with reference to design goals/principles/heuristics/patterns and discuss alternatives you considered and tradeoffs you made. If you used design pattern(s) explain which you used and why you used them, if you did not use any design patterns explain why not. Turn this in as a new `extension-justification.pdf` file.
 * **Updated object model:** Update your object model in `object-model.pdf` to reflect your extension mechanisms and the *Demeter* card.
-* **Update justification for building action:** Extend your discussion in `state-justification.pdf` of how the game validates and performs a build action assuming that *the active player has the Demeter card* and the opposing player has no card. Update both the justification and the object-level interaction diagram.
+* **Update justification for building action:** Extend your discussion in `build-justification.pdf` of how the game validates and performs a build action assuming that *the active player has the Demeter card* and the opposing player has no card. Update both the justification and the object-level interaction diagram.
 
 You do not need to update `state-justification.pdf`. We will grade the design documents with a similar rubric to Homework 3, so if you have unaddressed grading feedback, you might want to take this into consideration when refining the documents.