Add info about default values to describe

Change-Id: I9919e0d366b56ac17e7b606aa5aa0ae048b447c3
diff --git a/src/static_schema.hpp b/src/static_schema.hpp
index 554d83a..0d2bdff 100644
--- a/src/static_schema.hpp
+++ b/src/static_schema.hpp
@@ -51,6 +51,7 @@
     bool listHasKey(const schemaPath_& location, const ModuleNodePair& node, const std::string& key) const override;
     bool leafIsKey(const std::string& leafPath) const override;
     bool isConfig(const std::string& leafPath) const override;
+    std::optional<std::string> defaultValue(const std::string& leafPath) const override;
     const std::set<std::string> listKeys(const schemaPath_& location, const ModuleNodePair& node) const override;
     yang::TypeInfo leafType(const schemaPath_& location, const ModuleNodePair& node) const override;
     yang::TypeInfo leafType(const std::string& path) const override;