Function mod_utilities::unescape_str_into

pub fn unescape_str_into(source: &str, dest: &mut String)

Unescape special character sequences into their literal equivalent

For example \n becomes a real new line character

Expects utf escapes to be in the format \uXXXX where X are hex digits

This version copies onto the end of an existing String, use unescape_str to use a new String

Note that if the last char of the String is an unaccompanied backslash \, this is considered an invalid escape sequence and it is simply discarded