Codechange: Add missing override specifiers.

src/station_base.h

@@ -538,7 +538,7 @@ public:
 		if (!st->TileBelongsToAirport(this->tile)) ++(*this);
 	}
 
-	inline TileIterator& operator ++()
+	inline TileIterator& operator ++() override
 	{
 		(*this).OrthogonalTileIterator::operator++();
 		while (this->tile != INVALID_TILE && !st->TileBelongsToAirport(this->tile)) {
@@ -547,7 +547,7 @@ public:
 		return *this;
 	}
 
-	virtual std::unique_ptr<TileIterator> Clone() const
+	std::unique_ptr<TileIterator> Clone() const override
 	{
 		return std::make_unique<AirportTileIterator>(*this);
 	}