Improve document of cv::RotatedRect for #23335#23342fix#23335
### 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
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
Usage of imread(): magic number 0, unchecked result
* docs: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* samples, apps: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* tests: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* doc/py_tutorials: check imread() result
- allow installing samples sources on all platforms
even if BUILD_EXAMPLES is disabled, fixed minor
issues in sources installation process
- use 'example_<group>_<name>' scheme for target and binary file naming
- use single function for sample executable creation
* Add a new interface for hough transform
* Fixed warning code
* Fix HoughLinesUsingSetOfPoints based on HoughLinesStandard
* Delete memset
* Rename HoughLinesUsingSetOfPoints and add common function
* Fix test error
* Change static function name
* Change using CV_Assert instead of if-block and add integer test case
* I solve the conflict and delete 'std :: tr1' and changed it to use 'tuple'
* I deleted std::tr1::get and changed int to use 'get'
* Fixed sample code
* revert test_main.cpp
* Delete sample code in comment and add snippets
* Change file name
* Delete static function
* Fixed build error
