Returns a GithubLink to a raw content.

def as_raw_link(self):
        """Returns a GithubLink to a raw content.
        """
        if self.link_type == "raw":
            return self # Can be discussed if we need an hard copy, or fail
        if self.link_type != "blob":
            raise ValueError("Cannot get a download link from a tree link")
        return self.__class__(
            self.gitid,
            "raw",
            self.branch_or_commit,
            self.path,
            self.token
        )