Bug in logic to skip big or incomplete graphs

[mscfd]

The condition in the if line in

        # Do not render overly large graphs.
        if len(self.added) > self.max_nodes and self.warn:
            warn(
                f"Not showing graph {self.ident} as it would exceed the maximal number of {self.max_nodes} nodes"
            )
            return ""

in graphs.py (line ca. 900) has been mangled in commit b497ad8.

Independently of self.warn, if the first condition holds, then return an empty string.

There is another such test below this code block.

[ZedThree]

Thanks for catching this @mscfd!