[Docs] Mutex, Sem, and Deadlocks explanation

[wxkim]

What does the documentation currently state or lack?
Please paste the relevant snippet if possible.

Suggested Change or Improvement.
Clearly explain and justify your proposed update, clarification, or addition.

Documentation Impact
How significant is this update to the overall understanding of the tutorial?

• Minor (grammar, formatting, small typo)
• Moderate (clarification, additional example, rewording)
• Major (missing explanation, incorrect or obsolete information, structural change)

Additional context
Add any other context or screenshots about the feature request here.