libyang DOC fix some of the doxygen reference issues
diff --git a/Doxyfile.in b/Doxyfile.in
index e47a7ae..5bb0916 100644
--- a/Doxyfile.in
+++ b/Doxyfile.in
@@ -783,8 +783,10 @@
 
 INPUT                  = ./src/libyang.h \
 			 ./src/context.h \
+			 ./src/tree.h \
                          ./src/tree_schema.h \
                          ./src/plugins_exts.h \
+                         ./src/tree_data.h \
                          ./src/log.h \
                          ./src/set.h \
                          ./src/dict.h