Add hint about activating the DLC

src/css/states/main_menu.scss

@@ -256,6 +256,12 @@
             }
         }
 
+        > .hint {
+            @include SuperDuperSmallText;
+            @include S(margin-top, 10px);
+            @include S(width, 200px);
+        }
+
         > .dlcLogo {
             @include S(width, 190px);
         }

src/js/states/main_menu.js

@@ -120,6 +120,9 @@ export class MainMenuState extends GameState {
                         <button class="styledButton puzzleDlcGetButton">${
                             T.mainMenu.puzzleDlcViewNow
                         }</button>
+                        <span class="hint">
+                            ${T.puzzleMenu.dlcHint}
+                        </span>
                     </div>`
                         : ""
                 }