1Writer (and on desktop, Obsidian and Zettlr) has this feature. I'd rather use Editorial than 1Writer, though: Piped wikilinks, which lets you type [[Some document name]] and then you can tap those links to go to that document, provided it exists in the same directory as current file. Note: you don’t have to type extensions.
It’s very, very, very convenient and useful. You can have a simple wiki between documents in the same directory. Great for eg. zettelkasting.
This would make Editorial complete for me!
/ Henrik