docs: Predefine missing DECL_FINAL macro in doxygen configuration file

Change-Id: Ic7e161bba091b49fe507f913259f53f44d49e862
diff --git a/docs/doxygen.conf.in b/docs/doxygen.conf.in
index 790673e..7b9fa67 100644
--- a/docs/doxygen.conf.in
+++ b/docs/doxygen.conf.in
@@ -1929,7 +1929,8 @@
                          PUBLIC_WITH_TESTS_ELSE_PROTECTED=protected \
                          PROTECTED_WITH_TESTS_ELSE_PRIVATE=private \
                          VIRTUAL_WITH_TESTS \
-                         DECL_CLASS_FINAL=final
+                         DECL_CLASS_FINAL=final \
+                         DECL_FINAL=final
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The