Clean up C# tutorial links that were in C

[plantindesk]

Removed duplicate C# tutorial links from the list in C

What does this PR do?

Remove resource(s): The C section contained two C# tutorial links that were duplicates of the links already present in the dedicated C# section. This PR removes those duplicates to keep the list accurate and properly categorize.

For resources

Description

The C section contained two C# tutorial links that were duplicates of the links already present in the dedicated C# section. This PR removes those duplicates to keep the list accurate and properly categorized.

Why is this valuable?

• Fixes categorization errors
• Reduces duplication
• Keeps the resource list clean and easier to navigate

Checklist:

• Searched for duplicates
• Ensured alphabetical order in the updated list
• Used an informative name for the PR

Follow-up

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

[github-actions]

Linter failed, fix the error(s):

free-programming-books/more/free-programming-interactive-tutorials-en.md
77:1-77:57  warning  Incorrect number of blank lines between last section and next heading  blank-lines-1-0-2  remark-lint