[Docs] Mutex, Sem, and Deadlocks explanation

**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.