[Docs] No declarations of type Name and Description on Docs injection sample

[np-kyokyo]

https://injector.readthedocs.io/en/stable/terminology.html

I was trying out the code in the terminology section of the sample above , but there was no description of how we should specifically declare type Name and Description, which took me a bit of time.
Finally, I found out that it works fine by declaring them as:

from typing import NewType

Name = NewType("Name", str)
Description = NewType("Description", str)

(ref.#144)

But, I feel that this should be written in the Injection section of the sample.

[davidparsson]

Thanks @np-kyokyo, that sounds reasonable. Are you willing to open a pull request with those changes?