missing TypeScript declaration file

[Zamiell]

Now that ESLint 9 is released and everyone is migrating to flat config, importing the plugin into a flat config by following the official documentation actually results in a red squiggly line, because no declaration file exists (when using checkJs and/or @ts-check).

I suspect many/most users will be using TypeScript to validate that their new flat configs do not have typos in them. Thus, shipping a declaration file for this plugin would really be appreciated!