FSH strings support the escape sequences that FHIR already defines as valid in its regex for strings: \r, \n, and \t. Strings MUST be delimited by non-directional (neutral) quotes. Left and right directional quotes (unicode U+201C and U+201D) sometimes automatically inserted by "smart" text editors SHALL NOT be accepted. Left and right directional single quotes (U+2018 and U+2019) SHALL NOT be accepted in contexts requiring a single quotation mark.

As the non-accepted characters are mentioned with Unicode, I suggest adding the Unicode for the accepted ones as well.