WASHINGTON — President Donald Trump gives few news conferences, and when one came Friday it was sudden, unexpected and chaotic. The president walked to the portion of the White House lawn that reporters frequently use to give stand-up shots and gave an interview with Steve Doocy of “Fox & Friends,” his favorite morning show. When the Doocy interview ended, Trump talked to other reporters who had been standing nearby — a contentious session of journalists trying to shout over each other to get questions in.