DOC: fixing "unbalanced grouping commands" warnings

- error during test
- remove some small things left about the itkgroup

Author: albert-github

Modules/Core/Common/include/itkPlatformMultiThreader.h

@@ -182,3 +182,12 @@ class ITKCommon_EXPORT PlatformMultiThreader : public MultiThreaderBase
 
   /** wait for a thread in the threadpool to finish work */
   void SpawnWaitForSingleMethodThread(ThreadProcessIdType);
+
+  /** Friends of Multithreader.
+   * ProcessObject is a friend so that it can call PrintSelf() on its
+   * Multithreader. */
+  friend class ProcessObject;
+};
+} // end namespace itk
+#endif // itkPlatformMultiThreader_h
+

Utilities/Doxygen/CMakeLists.txt

@@ -108,13 +108,6 @@ mark_as_advanced(
   ITK_DOXYGEN_XML
   ITK_DOXYGEN_SERVER_BASED_SEARCH)
 
-if(Python3_EXECUTABLE)
-  set(ITK_DOXYGEN_INPUT_FILTER "${Python3_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/itkgroup.py")
-
-else()
-  set(ITK_DOXYGEN_INPUT_FILTER)
-endif()
-
 # -------------------------------------------------------------
 if(ITK_BUILD_DOCUMENTATION)
 

Wrapping/DoxygenConfig.cmake

@@ -52,7 +52,6 @@ set(DOXYGEN_EXAMPLE_PATH "${DOXYGEN_TEST_DIRS}")
 set(DOXYGEN_EXAMPLE_PATTERNS "*.cxx")
 set(DOXYGEN_EXAMPLE_RECURSIVE "YES")
 set(DOXYGEN_IMAGE_PATH "${ITK_SOURCE_DIR}/Documentation/Art" "${ITK_BINARY_DIR}/Utilities/Doxygen/Modules")
-set(DOXYGEN_INPUT_FILTER "${ITK_DOXYGEN_INPUT_FILTER}")
 set(DOXYGEN_FILTER_SOURCE_FILES "YES")
 set(DOXYGEN_SOURCE_BROWSER "YES")
 set(DOXYGEN_REFERENCED_BY_RELATION "YES")