Update Sum_of_digits_function.py

[ManasGupta1998]

Added a few comments

Fixes issue: #[Mention the issue number it fixes or add the details of the changes if it doesn't has a specific issue.]

Changes: [Add here what changes were made in this pull request.]

[AdiChat]

Kindly resolve the conflict. The folder mathematical-algorithms has been renamed to mathematical_algorithms. It will be good to merge after the minor change 👍

[ManasGupta1998]

@AdiChat I have renamed it

[arnavb]

Also, remove the capital s, make it lowercase.

[abdouskamel]

@AdiChat This one should be merged, no ?

[AdiChat]

This code achieves the same task and has the similar coding logic. 👍

[Vitorvgc]

I think that the intention of the PR is not to add a new implementation of the algorithm, but to add comments to clarify the code and support only Python 3 as stated in the Python style guide (here).

If so, @ManasGupta1998, you should update the current code rather than creating a new one.

[arnavb]

@ManasGupta1998 Here is another reminder to make the changes suggested by Vitorvgc so that this can be merged as soon as possible.