Appending "Bible as Markdown" Text Hierarchy with "ESV"

Here my situation: I need to append 30k+ Markdown Files with "(ESV)"

A friend of mine exported the entire Bible in Markdown for use in Obsidian. Each verse is a separate text file, and they are all named by the verse and organized by book and chapter.

What I need to do is append the translation initials at the end of each verse. For every single file!

So the file named Genesis 1.1.md with the contents:
In the beginning, God created the heavens and the earth.

Would become:
In the beginning, God created the heavens and the earth. (ESV)

I assume I would need to use match contents property, but how do I add (ESV) after whatever text happens to be inside the Markdown file?

From there I assume the Run Rules on Subfolders would be all I need?

Would love to know what rule to use to append text to end end of the text inside a Markdown file!

Thanks so much

Hazel does not have actions to modify the contents of files. You will need to write a script to handle that part for you.