add comment only

src/attachment.hh

@@ -66,6 +66,8 @@ namespace pEpMIME
     inline
     bool is_not_inline(const Attachment& att) { return att.is_inline() == false; }
     
+    // serialize all attachments, with the given delimiter
+    // NOTA BENE: It closes this multipart/* subtree by adding the proper final delimiter.
     void generate_attachments(std::string& out, const SAttachments& att, sv delimiter, bool(*filter)(const Attachment&) = all);
 
 }