For many Singaporeans, the prime minister’s wife Ho Ching and her prolific Facebook persona are one and the same.Once described as firmly publicity shy, Ho – the long-time head of Temasek Holdings, the island nation’s sovereign investment firm – has become one of the most closely watched personalities on social media in the city state.A recent This Week in Asia examination of data compiled by social-media tracking platform CrowdTangle showed the scale of her presence on Facebook, where her…