Gatsu can you share the content of your composer.json ? It seems s9e/text-formatter might have end up inside of it, but it shouldn't.
If s9e/text-formatter is inside of the file, you should remove that line, then run composer update s9e/text-formatter, this should fix the problem.
It's not related to the extension you are trying to install. It's a problem with the current state of your installation.