LENGTH MARK immune to capitalization

[Mercury13]

Also LENGTHENER, SEPARATOR, ITERATION MARK

❌ Kannada Ai length mark — will not!
❌ Oriya Ai length mark — will not!
✔ Soyombo vowel length mark
❌ Telugu Ai length mark
✔ Zanabazar square vowel length mark
✔ Kharoshthi vowel length mark
✔ Nyiakeng Puachue Hmong syllable lengthener
✔ Adlam vowel lengthener
✔ Ethiopic combining gemination and vowel length mark
✔ Ethiopic combining vowel length mark
✔ Garay vowel length mark
✔ Vai syllable lengthener
✔ Yi syllable iteration mark

But coined a counter-example: Klingon sign Length mark. You should hardwire it somehow