Hong Kong’s struggling restaurants were cautious to restock their kitchens and reluctant to roll out deeper discounts despite the resumption of evening dine-in services on Friday as operators said the relaxation of social-distancing measures offered them only little help.After dine-in services were banned from 6pm to 5am for nearly 1½ months amid the third wave of Covid-19 infections, restaurants will be allowed to serve guests until 9pm from Friday.Even though some eateries hope to see a small…