Fix character profile data fetching URL to correctly append the character ID and file extension

_includes/character-profile.html

@@ -15,7 +15,7 @@
   {% endif %}
 </div>
 <script>
-  fetch("{{ '/assets/game-data/characters/' + include.id | relative_url }}")
+  fetch("{{ '/assets/game-data/characters/' | append: include.id | append: '.json' | relative_url }}")
     .then(response => response.json())
     .then(character => {
       document.getElementById('name-{{ include.id }}').innerText = character.name;