WASHINGTON — Supreme Court nominee Merrick B. Garland praised lawyers for their work with low-income Washingtonians Thursday in his first public remarks since his nomination last month.The appearance marks the first time that Garland has spoken publicly at any length since Obama nominated him more than a month ago in the White House Rose Garden.His appearance Thursday was part of the White House’s effort to familiarize the country with the nominee by having him speak on a noncontroversial topic, free legal …