mIRC recognizes CRLF (or LF) as a line delimiter. This is fairly set, and fairly common not just in mIRC, but most (unicode aware) languages. You're certainly free to treat those characters as newlines, but I actually don't know any application that, for instance, treats a CR alone as a newline. Even Windows requires CRLF to actually mark a newline in most programs-- CR alone won't cut it, even though the "Unicode standard" declares it as a terminator.
Reading the implementation caveats in the section you linked further enforces the fact that very few languages actually handle Unicode newline characters.