docs give examples of tuples where they should be Vectors

https://github.com/CadQuery/cadquery/blob/e69b2f83bde43ad6a0159a72bc058165e684e72e/cadquery/selectors.py#L287-L338

The docs suggest `DirectionMinMaxSelector((0, 0, 1), True)`, but this code:
```python
from cadquery import *
test = Workplane("XY").box(1, 1, 1).faces(DirectionMinMaxSelector((0, 0, 1), True))
```
fails with `AttributeError: 'tuple' object has no attribute 'wrapped'`.

Changing the tuple to a Vector works:
```python
test = Workplane("XY").box(1, 1, 1).faces(DirectionMinMaxSelector(Vector(0, 0, 1), True))
```