Add FAQ entry for resolving broken themes/mods issue

This update adds a troubleshooting section in the FAQ to guide users on resolving issues with broken themes or mods. Instructions include locating the profiles folder, editing or deleting the `zen-themes.json` file, and restarting the browser. A precaution is also advised to back up the file before manual edits.

Author: Pdzly

content/docs/faq.mdx

@@ -128,3 +128,13 @@ Some users encounter the bug where websites are partialy transparent, to resolve
 2. Search for `browser.tabs.allow_transparent_browser`
 3. Set the flag to `false`
 4. **Restart the browser**
+
+## Themes/Mods broken
+
+Some users may encounter a bug where themes are broken, to resolve it to follow the steps below:
+
+1. Go to your profiles folder (Linux: `~/.zen/` or Flatpack: `~/.var/app/app.zen_browser.zen/zen/`, Windows: `%APPDATA%/zen/Profiles`)
+2. Go into the folder of the profile you are using (e.g. with the (release) suffix)
+3. Delete (or edit) the zen-themes.json file and restart the browser.
+
+Its recommended to backup the file before updating it manually. By editing you could break the browser