Make `.` a line continuation operator

[edA-qa]

There is a common syntax that might benefit from line continuation:

```
some.
  very(args).
  long(args).
  chain(args).
  end()
```

This may be desired over:

```
(some.
  very(args).
  long(args).
  chain(args).
  end()
)
```

I don't see any immediate reason how this would be ambiguous. I'd like to be careful here though, since it's just another operator, and no other operator would provide this ability. Perhaps it's better to wait for cases where it arises to compare syntax.