G-API: Fix various Doxygen isses for the 4.5.1 release

modules/gapi/include/opencv2/gapi/core.hpp

@@ -1153,6 +1153,7 @@ GAPI_EXPORTS GMat bitwise_xor(const GMat& src1, const GScalar& src2);
 
 
 /** @brief Inverts every bit of an array.
+
 The function bitwise_not calculates per-element bit-wise inversion of the input
 matrix:
 \f[\texttt{dst} (I) =  \neg \texttt{src} (I)\f]

modules/gapi/include/opencv2/gapi/gcommon.hpp

@@ -204,12 +204,12 @@ template<typename... Ts> GCompileArgs compile_args(Ts&&... args)
     return GCompileArgs{ GCompileArg(args)... };
 }
 
+namespace gapi
+{
 /**
  * @brief Retrieves particular compilation argument by its type from
  *        cv::GCompileArgs
  */
-namespace gapi
-{
 template<typename T>
 inline cv::util::optional<T> getCompileArg(const cv::GCompileArgs &args)
 {

modules/gapi/include/opencv2/gapi/imgproc.hpp

@@ -1344,6 +1344,7 @@ Output image is 8-bit unsigned 3-channel image @ref CV_8UC3.
 GAPI_EXPORTS GMat BGR2RGB(const GMat& src);
 
 /** @brief Converts an image from RGB color space to gray-scaled.
+
 The conventional ranges for R, G, and B channel values are 0 to 255.
 Resulting gray color value computed as
 \f[\texttt{dst} (I)= \texttt{0.299} * \texttt{src}(I).R + \texttt{0.587} * \texttt{src}(I).G  + \texttt{0.114} * \texttt{src}(I).B \f]
@@ -1370,6 +1371,7 @@ Resulting gray color value computed as
 GAPI_EXPORTS GMat RGB2Gray(const GMat& src, float rY, float gY, float bY);
 
 /** @brief Converts an image from BGR color space to gray-scaled.
+
 The conventional ranges for B, G, and R channel values are 0 to 255.
 Resulting gray color value computed as
 \f[\texttt{dst} (I)= \texttt{0.114} * \texttt{src}(I).B + \texttt{0.587} * \texttt{src}(I).G  + \texttt{0.299} * \texttt{src}(I).R \f]

modules/gapi/include/opencv2/gapi/infer/parsers.hpp

@@ -108,8 +108,8 @@ detection is smaller than confidence threshold, detection is rejected.
 relative box intersection area required for rejecting the box with a smaller confidence.
 If 1.f, nms is not performed and no boxes are rejected.
 @param anchors Anchors Yolo network was trained with.
-@note The default anchor values are taken from openvinotoolkit docs:
-https://docs.openvinotoolkit.org/latest/omz_models_intel_yolo_v2_tiny_vehicle_detection_0001_description_yolo_v2_tiny_vehicle_detection_0001.html#output.
+@note The default anchor values are specified for YOLO v2 Tiny as described in Intel Open Model Zoo
+<a href="https://github.com/openvinotoolkit/open_model_zoo/blob/master/models/public/yolo-v2-tiny-tf/yolo-v2-tiny-tf.md">documentation</a>.
 @return a tuple with a vector of detected boxes and a vector of appropriate labels.
 */
 GAPI_EXPORTS std::tuple<GArray<Rect>, GArray<int>> parseYolo(const GMat& in,