Update lecture-python sources with latest updates

[mmcky]

This PR updates the source files from lecture-python (dbd838d) using sphinx-tomyst (b06cacb)

@shlff this PR should contain all of your recent PR's that have been merged in addition to changes from Tom and John (over the past two weeks).

If you could take a look to see it looks as expected (from your commits) that would be great.

[mmcky]

Note: this will be missing the 6 lectures that require code execution until #16 is merged.

[mmcky]

@shlff I am going to merge this now but when you get the chance I'd appreciate you taking a quick look at the diff and let me know if it looks about right -- with regards to your recent changes. I have converted this from lecture-python using sphinx-tomyst

[shlff]

Great thanks for your nice work, @mmcky . Sorry for my late reply. sphinx-tomyst is really cool!

I checked all this PR's changes, most of which look right except the one for lecture short_path.md:

Since it is in myst, so the context after the change in that lecture (the left in the above screenshot) should be:

• (Graphs such as the one above are called **weighted [directed graphs](https://en.wikipedia.org/wiki/Directed_graph)**.)

Do you want me to submit a PR to correct this?

I will check these more carefully again, compared with my merged PRs in lecture-python.

Btw, should I submit my next PRs for improving lectures in this repo?

[mmcky]

@shlff looking at the source rst this seems correct

(Graphs such as the one above are called **weighted `directed graphs <https://en.wikipedia.org/wiki/Directed_graph>`_**.)

[mmcky]

@shlff oh I see the issue -- thanks. It should be updated. Would you mind setting up a new PR in this repo with the update and tag it as manual-change

Can you also document this issue on sphinx-tomyst issue register as a bug