Merge pull request #29220 from omrope79:doc_optimizations_v4

[FOLLOW UP] : Documentation optimizations for the new Sphinx structure #29220

### Pull Request Readiness Checklist

This PR serves as a follow-up to the new documentation system introduced in [#29206](https://github.com/opencv/opencv/pull/29206)
Co-authored by: @abhishek-gola @kirtijindal14 @Akansha-977 @Prasadayus @varun-jaiswal17

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

modules/dnn/perf/perf_net.cpp

@@ -145,8 +145,7 @@ PERF_TEST_P_(DNNTestNetwork, SSD)
 {
     applyTestTag(CV_TEST_TAG_DEBUG_VERYLONG);
 
-    // The Caffe-SSD specific handling lives in the new engine importer only;
-    // the classic importer can no longer load this model.
+    // SSD_VGG16's specialized preprocessing is handled by the new engine importer only.
     auto engine_forced = static_cast<dnn::EngineType>(
         utils::getConfigurationParameterSizeT("OPENCV_FORCE_DNN_ENGINE", dnn::ENGINE_AUTO));
     if (engine_forced == dnn::ENGINE_CLASSIC)
@@ -190,9 +189,7 @@ PERF_TEST_P_(DNNTestNetwork, OpenPose_pose_mpi_faster_4_stages)
 
     if (backend == DNN_BACKEND_INFERENCE_ENGINE_NN_BUILDER_2019 && (target == DNN_TARGET_MYRIAD || target == DNN_TARGET_HDDL))
         throw SkipTestException("");
-    // The same .caffemodel but modified .prototxt
     // See https://github.com/CMU-Perceptual-Computing-Lab/openpose/blob/master/src/openpose/pose/poseParameters.cpp
-    // processNet("dnn/openpose_pose_mpi.caffemodel", "dnn/openpose_pose_mpi_faster_4_stages.prototxt", cv::Size(368, 368));
     processNet("dnn/onnx/models/openpose_pose_mpi.onnx", "", cv::Size(368, 368));
 }