make clang happy (func override)

alib2data/src/graph/directed/DirectedGraph.h

@@ -83,7 +83,7 @@ public:
 	static DirectedGraph parse(std::deque<sax::Token>::iterator& input);
-	void compose(std::deque<sax::Token>& out) const;
+	void compose(std::deque<sax::Token>& out) const override;
 private:
 	void init();

alib2data/src/graph/undirected/UndirectedGraph.h

@@ -83,7 +83,7 @@ public:
 	static UndirectedGraph parse(std::deque<sax::Token>::iterator& input);
-	void compose(std::deque<sax::Token>& out) const;
+	void compose(std::deque<sax::Token>& out) const override;
 private:
 	void init();