I've made the suggested changes. Let me know if you want me to squash any commits.

@Iain-S I've pushed a commit, mostly to make the code style more like the rest of the code base (note that we do not use Black).

I've also noticed that this state:

        "multi_string": [
            (r"[^`]+", String),
            (r"```", String, "#pop"),
        ],

does not allow single backticks inside ```-delimited strings. I suppose this is not intentional, right? In that case, it needs an extra rule (r"`", String)`.

I suppose this is not intentional, right? In that case, it needs an extra rule (r"`", String)`.

True, that was an oversight. I've added your suggested tuple and a test to confirm that it works.

LGTM now, thank you.