By Devjyot Ghoshal and Uditha Jayasinghe COLOMBO (Reuters) – Thousands of people queued for cooking gas and petrol in Sri Lanka’s commercial capital on Friday and Prime Minister Ranil Wickremesinghe warned of a food shortage as the island nation battles a devastating economic crisis. Lines formed in many parts of Colombo, a city of around 900,000 people, as residents tried to stock up on fuel, which is mostly imported and is in extremely short supply with the government running out of foreign exchange. “Only about 200 cylinders were delivered, even though there were about 500 people,” said Moh…