Fix missing `max_line_length` by adding deprecated shadow-selector
Fix missing `max_line_length` by adding deprecated shadow-selector

As an undocumented uncommunicated side-effect the pure atom-text-editor selector does not take effect during the transition of the shadow dom as the folling answer of lee-dom states:

lee-dohm	[4:57 AM]
You could specify the styles both ways ... something like `atom-text-editor, atom-text-editor::shadow {`

sindresorhus/atom-editorconfig,florianb/atom-editorconfig