docs(js): Fix Mat.clone() documentation to use mat_clone() for deep copy #27985
- Update code example to use ```mat_clone()``` instead of ```clone()```
- Add explanatory note about shallow copy issue due to Emscripten embind
Problem
- OpenCV.js documentation shows ```Mat.clone()``` usage, but this method performs shallow copy instead of deep copy due to Emscripten embind limitations, causing unexpected behavior where modifications to cloned matrices affect the original.
Related Issues and PRs
- Fixes documentation aspect of issue #27572
- Related to PR #26643 (js_clone_fix)
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake