fixed a few compile errors/warnings in 2.4 branch of the docs

modules/contrib/doc/retina/index.rst

@@ -208,7 +208,7 @@ Retina::getMagno
 Retina::getParameters
 +++++++++++++++++++++
 
-.. ocv:function:: struct Retina::RetinaParameters Retina::getParameters()
+.. ocv:function:: Retina::RetinaParameters Retina::getParameters()
 
     Retrieve the current parameters values in a *Retina::RetinaParameters* structure
 
@@ -323,7 +323,8 @@ Retina::RetinaParameters
 ========================
 
 .. ocv:struct:: Retina::RetinaParameters
-This structure merges all the parameters that can be adjusted threw the **Retina::setup()**, **Retina::setupOPLandIPLParvoChannel** and **Retina::setupIPLMagnoChannel** setup methods
+
+  This structure merges all the parameters that can be adjusted threw the **Retina::setup()**, **Retina::setupOPLandIPLParvoChannel** and **Retina::setupIPLMagnoChannel** setup methods
 Parameters structure for better clarity, check explenations on the comments of methods : setupOPLandIPLParvoChannel and setupIPLMagnoChannel. ::
 
     class RetinaParameters{

modules/gpu/doc/image_processing.rst

@@ -873,15 +873,16 @@ gpu::FastNonLocalMeansDenoising
 -------------------------------
 .. ocv:class:: gpu::FastNonLocalMeansDenoising
 
-    class FastNonLocalMeansDenoising
-    {
-    public:
-        //! Simple method, recommended for grayscale images (though it supports multichannel images)
-        void simpleMethod(const GpuMat& src, GpuMat& dst, float h, int search_window = 21, int block_size = 7, Stream& s = Stream::Null())
-
-        //! Processes luminance and color components separatelly
-        void labMethod(const GpuMat& src, GpuMat& dst, float h_luminance, float h_color, int search_window = 21, int block_size = 7, Stream& s = Stream::Null())
-    };
+    ::
+
+        class FastNonLocalMeansDenoising
+        {
+        public:
+            //! Simple method, recommended for grayscale images (though it supports multichannel images)
+            void simpleMethod(const GpuMat& src, GpuMat& dst, float h, int search_window = 21, int block_size = 7, Stream& s = Stream::Null())
+            //! Processes luminance and color components separatelly
+            void labMethod(const GpuMat& src, GpuMat& dst, float h_luminance, float h_color, int search_window = 21, int block_size = 7, Stream& s = Stream::Null())
+        };
 
 The class implements fast approximate Non Local Means Denoising algorithm.