✨ Add 'Contains' function for 'Rectangle'

This will be useful for various bound checks throughout the code.

Source/engine/rectangle.hpp

@@ -8,6 +8,14 @@ namespace devilution {
 struct Rectangle {
 	Point position;
 	Size size;
+
+	constexpr bool Contains(Point point) const
+	{
+		return point.x >= this->position.x
+		    && point.x <= (this->position.x + this->size.width)
+		    && point.y >= this->position.y
+		    && point.y <= (this->position.y + this->size.height);
+	}
 };
 
 } // namespace devilution