Myanmar police detained a Japanese freelance journalist at a protest in the commercial capital of Yangon, a colleague said on Friday, in the first detention of a foreign reporter since the military coup on February 1.Yuki Kitazumi, who runs a media production company and used to be a journalist for the Japanese business daily, the Nikkei, according to his Facebook page and interviews with online media, was arrested on Friday morning.“According to witnesses, he was beaten on his head but he was…