As the world mourns the loss of Jimmy Buffett, celebrities have been taking to social media to pay tribute to the "Margaritaville" singer, who died Friday at age 76. Among those honouring Buffett is Elton John, who praised Buffett in a post he shared on Instagram Story. [readmore label="READ MORE: " link="https://etcanada.com/news/1017762/jimmy-buffett-margaritaville-singer-dead-at-76/" /] "Jimmy Buffett…