Fix black diagonal line — remove stray backslash from HTML comment

index.html

@@ -107,7 +107,7 @@
         <div class="npc-bubble" id="npc-bubble">!</div>
         <div class="map-npc" id="map-npc"></div>
       </div>
-      <!-- Player stays fixed to viewport, only Y moves -->\
+      <!-- Player stays fixed to viewport, only Y moves -->
       <div class="player-bubble" id="player-bubble">...</div>
       <div class="map-player" id="map-player"></div>
       <!-- Hints overlay the viewport, not the world -->