By Mark Trevelyan LONDON (Reuters) -Senegal’s President Macky Sall said Russia’s Vladimir Putin had told him on Friday he was ready to enable the export of Ukrainian grain to ease a global food crisis that is hitting Africa especially hard. “President #Putin has expressed to us his willingness to facilitate the export of Ukrainian cereals,” Sall wrote on Twitter after meeting Putin in his role as chairman of the African Union. Russia was also ready to ensure the export of its own wheat and fertiliser, Sall said after the talks in the Russian Black Sea resort of Sochi on day 100 of Putin’s inva…