Typo on slide 25

Hi, just noticed a small typo, a `b` should be an `i` on slide 25 at https://www.dabeaz.com/generators/Generators.pdf

What's there:

```python
for i in b: print(b, end=' ')
```

What I'd expect:

```python
for i in b: print(i, end=' ')
```

Cheers.