de:
  i18n:
    transliterate:
      rule:
        ä: "ae"
        é: "e"
        ü: "ue"
        ö: "oe"
        Ä: "Ae"
        Ü: "Ue"
        Ö: "Oe"
        ß: "ss"

de:
  i18n:
    transliterate:
      rule:
        ä: "ae"
        é: "e"
        ü: "ue"
        ö: "oe"
        Ä: "Ae"
        Ü: "Ue"
        Ö: "Oe"
        ß: "ss"
        ẞ: "SS"

Add transliteration rule for capital sharp s
Add transliteration rule for capital sharp s

The letter ẞ is the capital variant of the small letter ß used in German.
It's pretty rare in the wild, but here it is for completeness sake!

Also see https://en.wikipedia.org/wiki/%C3%9F#Development_of_a_capital_form