German President Frank-Walter Steinmeier has wished Britain's King Charles III a quick recovery as he undergoes treatment for an undisclosed form of cancer. "It was with great regret that I heard of your illness. Allow me to extend my warmest wishes for a speedy and complete recovery, both personally and on behalf of my German compatriots," Steinmeier wrote in a letter, according to the president's office on Tuesday. "I am sure that you are in the best medical hands," he continued. "You are a gr