need better documentation in Reddit's port

### Is there an existing issue outlining your problem?

- [x] I am using the latest version of the provided userstyle.
- [x] I have searched the existing issues and they do not solve my problem.

### What userstyles are you seeing the problem on?

lbl:reddit

### Describe your problem.

I just noticed that some area are not themed and I'm not comfortable with it. It was at credit bar on a post, and I thought it was a bug, until I found the solution after many attempts of browser cross-checking.

It's because I turned on the `use community themes` options in `Settings > Preferences > Experiece > Use Commuinty Themes`. If turns off, the credit bar goes themed and the catppuccin looks normal.

Though it was user's error, I think it would be better if we provied some tips to avoid conflicts like this on the documentation, especially cappuccin reddit userstyles repo. So any newbies like me can avoid this in further. Thank you!

note:
*I haven't check if this bug also happen in another user

### Attach screenshots.

_No response_

### What browser(s) are you seeing the problem on?

Mozilla Firefox 146.0.1; Chromium 143.0.7499.169

### Any additional comments?

_No response_

The issue identifies Reddit's userstyle and the Settings > Preferences > Experience > Use Community Themes path, but names no documentation file or test. Start by locating the Reddit userstyle documentation, then explain this theme conflict; done means newcomers can find the guidance before enabling the option.

Written by the indexing model from the issue text.