Shorthand syntax for "Auto" reactions

"Reactions" are unobserved side effects in response to an observed computation.

The current way to do this:

```ts
auto(() => {
// Observed computation here
noto(() => {
// Unobserved side effects here
})
})
```

The proposed way to do this:

```ts
auto(
() => {
// Observed computation here
},
result => {
// Unobserved side effects here
}
)
```

The bonus (of course) being that you don't need to import `noto`.