Marian docstring
Author: traveler-pinkie
Pull request: yes

# What does this PR do?
related to #16292
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 @ydshieh, @patrickvonplaten 
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Comments:
I need some help. This is my first time contributing to a project ever. I'm getting familiar with the process of git, and I've tried to follow the instructions layed out on the [Community Event] Doc Tests Sprint #16292. I ran the doc test locally and received to errors. But upon further inspection, I can't seem to find what the issue is. Please if you can offer come guidance on what I'm doing wrong and how to progress. I'm working on modeling_tf_marian.py 

![Screenshot 2022-10-13 223655](https://user-images.githubusercontent.com/75712292/195965122-349001fc-b173-488c-a790-cede71b8bf4a.png)


@traveler-pinkie sorry for being late here. Are you still interested in working on Marian config files?

@ydshieh . Thanks for commenting back. But I think at the moment I should probably study a little bit more. It looks like I was having more difficulty then I should have. With my skills currently. I think it's best if someone else works on it. Sorry and thank you