Merge pull request #27730 from Kumataro:fix27729

doc: fix doxygen warnings for imgcodecs, flann and objdetect #27730

Close https://github.com/opencv/opencv/issues/27729

### 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

doc/opencv.bib

@@ -1431,14 +1431,6 @@
   publisher = {Kluwer Academic Publishers},
   url = {https://www.face-rec.org/algorithms/Boosting-Ensemble/16981346.pdf}
 }
-@inproceedings{wang2016iros,
-  author = {John Wang and Edwin Olson},
-  title = {{AprilTag} 2: Efficient and robust fiducial detection},
-  booktitle = {Proceedings of the {IEEE/RSJ} International Conference on Intelligent Robots and Systems {(IROS)}},
-  year = {2016},
-  month = {October},
-  url = {https://april.eecs.umich.edu/pdfs/wang2016iros.pdf}
-}
 @misc{Welch95,
   author = {Welch, Greg and Bishop, Gary},
   title = {An introduction to the Kalman filter},

modules/flann/include/opencv2/flann/general.h

@@ -54,12 +54,12 @@ public:
 
 #define FLANN_THROW(TYPE, STR) throw FLANNException(STR)
 
+//! @endcond
+
 #else
 
 #define FLANN_THROW(TYPE, STR) CV_Error(TYPE, STR)
 
 #endif
 
-//! @endcond
-
 #endif  /* OPENCV_FLANN_GENERAL_H_ */

modules/imgcodecs/include/opencv2/imgcodecs.hpp

@@ -184,7 +184,7 @@ enum ImwriteTiffResolutionUnitFlags {
 };
 
 enum ImwriteEXRTypeFlags {
-       /*IMWRITE_EXR_TYPE_UNIT = 0, //!< not supported */
+       // IMWRITE_EXR_TYPE_UNIT = 0, // not supported
        IMWRITE_EXR_TYPE_HALF   = 1, //!< store as HALF (FP16)
        IMWRITE_EXR_TYPE_FLOAT  = 2  //!< store as FP32 (default)
      };

modules/objdetect/doc/objdetect.bib

@@ -16,7 +16,8 @@
   title = {{AprilTag} 2: Efficient and robust fiducial detection},
   booktitle = {Proceedings of the {IEEE/RSJ} International Conference on Intelligent Robots and Systems {(IROS)}},
   year = {2016},
-  month = {October}
+  month = {October},
+  url = {https://april.eecs.umich.edu/pdfs/wang2016iros.pdf}
 }
 
 @mastersthesis{Xiangmin2015research,