Wrap sequence in output file

[alvanuffelen]

A common convention is to wrap lines at 60 characters in a FASTA file.
Would it be possible to add an option to wrap the sequences when writing out to a file?
For example:

/// Write a Fasta record with given id, optional description and sequence.
    pub fn write(&mut self, id: &str, desc: Option<&str>, seq: TextSlice<'_>) -> io::Result<()> {
        self.writer.write_all(b">")?;
        self.writer.write_all(id.as_bytes())?;
        if let Some(desc) = desc {
            self.writer.write_all(b" ")?;
            self.writer.write_all(desc.as_bytes())?;
        }
        self.writer.write_all(b"\n")?;
        for chunk in seq.chunks(wrap) {
            self.writer.write_all(chunk)?;
            self.writer.write_all(b"\n")?;
        }
        self.writer.write_all(b"\n")?;

        Ok(())
    }

[dcroote]

Yes and in fact there is an open PR for this by @openpaul: #490