Hong Kong’s struggling businesses will get a shot in the arm with a HK$24 billion (US$3.1 billion) third round of Covid-19 relief funding unveiled on Tuesday that will shrink the city’s fiscal reserves to about a year’s worth of government spending, a level last reached in the aftermath of the Sars health crisis.Coronavirus vaccines and quarantine capacity upgrades form part of the administration’s latest package, as well as cash injections for various sectors, and the extension of both rental…