docs/api/Doxyfile.cmake - remove CLANG options

to quiet the doxygen warnings:
"belongs to an option that was not enabled at compile time."

docs/api/Doxyfile.cmake

@@ -1083,35 +1083,6 @@ USE_HTAGS              = NO
 
 VERBATIM_HEADERS       = NO
 
-# If the CLANG_ASSISTED_PARSING tag is set to YES then doxygen will use the
-# clang parser (see: http://clang.llvm.org/) for more accurate parsing at the
-# cost of reduced performance. This can be particularly helpful with template
-# rich C++ code for which doxygen's built-in parser lacks the necessary type
-# information.
-# Note: The availability of this option depends on whether or not doxygen was
-# generated with the -Duse_libclang=ON option for CMake.
-# The default value is: NO.
-
-CLANG_ASSISTED_PARSING = NO
-
-# If clang assisted parsing is enabled you can provide the compiler with command
-# line options that you would normally use when invoking the compiler. Note that
-# the include paths will already be set by doxygen for the files and directories
-# specified with INPUT and INCLUDE_PATH.
-# This tag requires that the tag CLANG_ASSISTED_PARSING is set to YES.
-
-CLANG_OPTIONS          =
-
-# If clang assisted parsing is enabled you can provide the clang parser with the
-# path to the compilation database (see:
-# http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html) used when the files
-# were built. This is equivalent to specifying the "-p" option to a clang tool,
-# such as clang-check. These options will then be passed to the parser.
-# Note: The availability of this option depends on whether or not doxygen was
-# generated with the -Duse_libclang=ON option for CMake.
-
-#TOO NEW CLANG_DATABASE_PATH    =
-
 #---------------------------------------------------------------------------
 # Configuration options related to the alphabetical class index
 #---------------------------------------------------------------------------