Feature request : Send email with contacts in CC

I create this post because I can't reopen

My lightweight proposition:
• add a CC checkbox near each contact in the Invoice view
• when generating email for the contact, in the same way as now, if the CC is checked, adjust the email:
- in the subject, add COPY
- in the body, add a block saying : The main invoice was sent to Contact XXX. You received this message as a copy for your information (or something like this...)