add rust books at free-programming-books-ko.md

[partrita]

What does this PR do?

Add resource(s)

For resources

Description

Why is this valuable (or not)?

I added an entry to the Rust book written in Korean. Additionally, I added a book about machine learning and corrected one typo.

How do we know it's really free?

I personally verified that the entire content is freely available to the public. Furthermore, the authors of the book published a physical copy through a publishing house after releasing the content online. Therefore, as it is nearly impossible to delete the already published book content from the internet, it will continue to be provided for free.

For book lists, is it a book? For course lists, is it a course? etc.

It is a book.

Checklist:

• [X] Read our contributing guidelines.
• [X] Search for duplicates.
• [X] Include author(s) and platform where appropriate.
• [X] Put lists in alphabetical order, correct spacing.
• [X] Add needed indications (PDF, access notes, under construction).
• [X] Used an informative name for this pull request.

Follow-up

• Check the status of GitHub Actions and resolve any reported warnings!