Improved readability of TensorFlow description.
Slightly altered the README file of TensorFlow to become more readable, and included a missing indefinite article in the same file.

![Screenshot 2023-03-14 at 18 46 42](https://user-images.githubusercontent.com/79566933/225093656-b3161274-1210-4705-957c-9a1e6ec8f68d.png)
