@extra-string/to-subscript (npm): Convert string to subscript characters, limited support.
Keywords: extra|string|standard|utility|method|text|manipulation|function|merferry|to|subscript|at|compare-function|digits|hex-digits|infix|is-infix|is-prefix|is-suffix|left|letters|lowercase|map-function|prefix|replace-function|right|size|suffix|test-function