expose FFFSType and friends

[masterkain]

can't import that type, can't use mount properly without insane workaround in a next.js ts project

#723

[wzulfikar]

I had similar issue (Next.js 14 with TS, @ffmpeg/ffmpeg ^0.12.15) but turns out FFFSType is already exported and this worked for me:

import { FFFSType } from "@ffmpeg/ffmpeg";

await ffmpeg.mount(FFFSType.WORKERFS, { files: [videoFile] }, inputDir);

// I was using this before and the type check would fail
await ffmpeg.mount("WORKERFS", { files: [videoFile] }, inputDir);

[masterkain]

that's because #723 got merged, so thanks for that