By Krystal Hu and Anirban Sen (Reuters) – Twitter Inc and its advisers were not sure at first how seriously to take him. Elon Musk’s $54.20-per-share offer price for the social media company on April 14 contained the digits 420, a reference to a trope for smoking marijuana. Financing documents he submitted last week in support of his bid were signed on April 20, abbreviated as 4/20. Such references harken back to his 2018 “funding secured” tweet stating that he was considering taking electric car maker Tesla Inc private for $420 per share. Tesla and Musk subsequently agreed to pay $20 million …