Variable themeOptionsConst

themeOptions: readonly [
    { label: "System"; value: "system" },
    { label: "Default"; value: "default" },
    { label: "Dark"; value: "dark" },
    { label: "Forest"; value: "forest" },
    { label: "Neutral"; value: "neutral" },
    { label: "Base"; value: "base" },
] = mermaidThemeOptions