App consider gemini links as invalid

[anedroid]

Describe the bug
I can't add a bookmark to interesting article that I found in geminispace, because app think this URL is invalid. Gemimi is a web protocol for plaintext-only websites. It has been created in 2019 as an answer to current bloated web where you are tracked everywhere and have no control over how websites look in your browser and what they do. You can read about gemini here:

=> https://gemini.circumlunar.space
=> https://geminiquickst.art

or through Gemimi:

=> gemini://gemini.circumlunar.space
=> gemini://geminiquickst.art

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Bookmarks'
2. Add new bookmark
3. Insert any gemimi link into 'URL'
4. Click 'back' to save bookmarl
5. Invalid URL

Expected behavior
Bookmark should be added.

Smartphone:

• Device: any
• OS: Android 11
• App Version: 1.0

Additional context
I have checked the source code to know how app validates URLs. It use android.webkit.URLUtil. In fact this tool rejects all URLs that is not http or https. Maybe the solution would be to validate using generic Regex, like /^\w+:\/+/ instead? I am sorry, but I don't know Kotlin nor Android development so I can't make a pull request.