opening plaintext files without .txt or equiv in-app

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**Is your feature request related to a problem? Please describe.**
As one of the things I use my nextcloud server for is syncing my dot files, I have quite a few plaintext files without file endings (or with more unusual filetypes like .kdl) that from time to time I'd like to edit on the go from my phone.

**Describe the solution you'd like**
The inbuilt plaintext editor, that opens by default for .md or .txt files should be able to handle these just fine, but isn't shown as an option in the "Open With" menu due to it being bound to only certain file type endings. Would it be possible to extend its use? This would probably require mimetype detection rather han simple file suffix binding.

**Describe alternatives you've considered**
- add a .txt to the end of a file I want to edit and remove it afterwards
- use a locally installed editor, most of which also have this issue

**Additional context**
N/A