fix: mermaid rendering broken after rehype-pretty-code bump (closes #638)

Jacky Zhao

2023-12-19 443cd53a1acf33ac0aaa34e0e75760d3da912d18

 quartz/plugins/transformers/syntax.ts

@@ -8,7 +8,11 @@
      [
        rehypePrettyCode,
        {
          theme: "css-variables",
          keepBackground: false,
          theme: {
            dark: "github-dark",
            light: "github-light",
          },
        } satisfies Partial<CodeOptions>,
      ],
    ]