Function decode_ml_basic_string 

pub(crate) fn decode_ml_basic_string<'i>(
    raw: Raw<'i>,
    output: &mut dyn StringBuilder<'i>,
    error: &mut dyn ErrorSink,
)

Parse multi-line basic string

;; Multiline Basic String

ml-basic-string = ml-basic-string-delim [ newline ] ml-basic-body
                  ml-basic-string-delim
ml-basic-string-delim = 3quotation-mark

ml-basic-body = *mlb-content *( mlb-quotes 1*mlb-content ) [ mlb-quotes ]

mlb-content = mlb-char / newline / mlb-escaped-nl
mlb-char = mlb-unescaped / escaped
mlb-quotes = 1*2quotation-mark