A file can contain statements, can be an invocation sender

We can invoke a (global) function from a file, like this:

```ts
x(1);
```

The MM has to support this, and maybe it means things like

```st
	file --|> namedEntity.
	file --|> #TFile.
        file --|> #TWithStatements. "TypeScript files can contain statements directly."
```

There may also be issues with Invocations, since a File is a sender (?)