Small typos on intro page

[menehune23]

https://course.fast.ai/#the-software-you-will-be-using (paragraph 2):

The fastai library one of the most popular libraries for adding this higher-level functionality on top of PyTorch.

should be:

The fastai library is one of the most popular libraries for adding this higher-level functionality on top of PyTorch.

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https://course.fast.ai/#how-do-i-get-started (paragraph 2):

Each video to designed to go with various chapters from the book.

should be:

Each video is designed to go with various chapters from the book.