include server plugin api in doxygen

cmake_templates/Doxyfile.in

@@ -593,7 +593,12 @@ INPUT                  = @CMAKE_SOURCE_DIR@/doc \
                          @CMAKE_SOURCE_DIR@/src/analysis/openstreetmap \
                          @CMAKE_SOURCE_DIR@/src/analysis/raster \
                          @CMAKE_SOURCE_DIR@/src/analysis/vector \
-                         @CMAKE_SOURCE_DIR@/src/plugins
+                         @CMAKE_SOURCE_DIR@/src/plugins \
+                         @CMAKE_SOURCE_DIR@/src/server/qgscapabilitiescache.h \
+                         @CMAKE_SOURCE_DIR@/src/server/qgsmapserviceexception.h \
+                         @CMAKE_SOURCE_DIR@/src/server/qgsrequesthandler.h \
+                         @CMAKE_SOURCE_DIR@/src/server/qgsserverfilter.h \
+                         @CMAKE_SOURCE_DIR@/src/server/qgsserverinterface.h
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is