message: Update source map example to be less misleading
  Fixes
diff: @@ -170,7 +170,7 @@ All you have to think about is how to manipulate the syntax tree, and Recast wil
  var result = recast.print(transform(recast.parse(source, {
  sourceFileName: "source.js"
  })), {
  - sourceMapName: "map.json"
  + sourceMapName: "source.min.js"
  });
  console.log(result.code); // Resulting string of code.
  