fixed a typo - Update W2D2_Tutorial3.ipynb

[ritog]

Solves #390

In the section titled Coding Exercise 3: Mixing Discrete Objects With Continuous Space, there is typo in the section. It says:

As you can seem, the similarity is destroyed, which is what we should expect.

But it should be:

As you can see, the similarity is destroyed, which is what we should expect.

Seem is changed to see.

[glibesyck]

Thank you @ritog! Indeed, it should be the way you indicated!