SYDNEY (Reuters) - Asian share markets made guarded gains on Tuesday amid cheery chatter about the chance of a Sino-U.S. trade deal, while investors were sanguine yet another vote on Brexit would still avert a hard exit for the UK.A holiday in Tokyo kept turnover light and MSCI's broadest index of Asia-Pacific shares outside Japan added a modest 0.3%.Futures for Japan's Nikkei were trading at 22,760, compared to Monday's index close at 22,548 . South Korean stocks rose 0.9% and Shanghai blue..