Billionaire Gautam Adani's group will raise Rs 21,000 crore (over $2.5 billion) through share sale in two group companies in the boldest comeback strategy after the ports-to-energy conglomerate was rocked by allegations of fraud levelled by a US short-seller.Adani Enterprises, the group's flagship firm, plans to raise Rs 12,500 crore while electricity transmission company Adani Transmission another Rs 8,500 crore, the companies said in stock exchange filings.The board of renewable energy arm, Adani Green Energy Ltd too was scheduled to meet on Saturday for a fundraise...