add feature 'location' that can locate where the Error throw in project file and not affect origin api

[JiajieZeee]

While developing a web application, I discovered the anyhow project, which significantly streamlined my development process and brought me great joy. However, I noticed that when generating error messages, the first stack unwinding operation incurs substantial performance overhead. Additionally, sifting through dozens of stack frames to locate the error source proved cumbersome.

This led me to explore alternatives for capturing error contexts and original throw locations without stack unwinding. I found a library called anyhow_ext that extends functionality by recording error locations, though it requires adding .dot() markers at relevant points.

I then considered: Could this be implemented as a native feature in anyhow? With AI assistance, I developed a solution that:

🛠️ Integrates error location tracking
⚡ Eliminates performance bottlenecks
✅ Maintains full backward compatibility
📚 Includes comprehensive test cases and documentation
I am excited to share this contribution and hope you and the community find it valuable!
appreciate.