A man handed himself in to police on Wednesday night saying he had killed his wife in a fight at their Hong Kong flat.The 37-year-old man, from Gambia, was arrested on suspicion of murder.He approached Wong Tai Sin Police Station at about 9.50pm, saying he killed the 40-year-old Filipino, who held a Hong Kong identity card. He said he had a physical fight with her in their subdivided To Kwa Wan flat that morning.Firefighters forced open the door to the flat, on Pang Ching Street, and found the…