E0003: a string literal that is never closed

A STRING literal is written between single quotes, a WSTRING literal between double quotes (Ed.3 6.3.3), and both end on the line they start. A quote inside the text is written $' or $".

msg := 'it's done';     (* E0003: the literal ends after "it" *)
msg := 'it$'s done';    (* fixed *)