[@types/emscripten]: `preRun`missing arg

Currently the type signature of `preRun` is `(() => void)[]`. Instead it should be more like

```ts
type singlePreRunType = ((arg: SWIPLModule) => void) | (() => void);
type preRunType = singlePreRunType | singlePreRunType[] | undefined;
```

as can be seen in the usage in https://github.com/eyereasoner/eye-js/pull/79/files

Also reported in https://github.com/rla/npm-swipl-wasm/issues/13