Update dependency markdown-it to v12

Author: renovate-bot

package-lock.json

@@ -15,7 +15,7 @@
     "highlight.js": "^10.5.0",
     "idb": "^6.0.0",
     "jquery": "^3.5.1",
-    "markdown-it": "^8.4.2",
+    "markdown-it": "^12.0.0",
     "markdown-it-emoji": "^2.0.0",
     "markdown-it-html5-embed": "^1.0.0",
     "markdown-it-task-lists": "^2.1.1",