Add other generated ligatures: ẞ, ß, ð, Þ, þ

[pelson]

Note that I've generated something with ChatGPT (@Carreau's prediction 😂):

This was using the prompt:

Take this image, and generate an image containing ẞ, ß, Æ, Œ, a, æ, œ, ð, Þ, þ characters in the same style. The a and æ should use double-story form.

Along with the original handwriting sample.

The only existing form that I could find anywhere in XKCD is https://xkcd.com/2763/ (Æ)

Originally posted by @pelson in #66

[panda667]

Pretty! Although I don't approve of AI usage for this (my personal beliefs please no one attack me), it does look good. But should the lowercase ß be slimmer and have the bottom loop stick out a bit?

[pelson]

Although I don't approve of AI usage for this

Totally fair. Personally (as you can see) I'm more open to it, but only strictly where we don't have any other option in the whole XKCD back-catalogue.

I would also be open to having a non-XKCD sample hand drawn by a knowledgeable person (i.e. human intelligence) so that we can keep the "no-AI generated character rule"... (turns out that normalising the width of the pen is reasonably doable).

The only existing form that I could find anywhere in XKCD is https://xkcd.com/2763/ (Æ)

Note that I actually used this glyph in https://github.com/ipython/xkcd-font/blob/master/xkcd-script/generator/extras/2763_linguistics_gossip_2x__AE.png, rather than the one from the AI generated form.