outrun/lib/shift_left.run

```doc
# Shift Left

Values which wish to implement the `<<` infix operator must implement this protocol.
```
protocol ShiftLeft, as: do
  ```doc
  Shift `self` left by `other` bits, returning an option.

  It is left up to the implementer to define when it should return `Some` or `None`.
  ```
  def shift(self: Self, other: Any): Option
end