code: function readFile (file) {
      if (!isFileRegistered(file)) { return undefined; }
  
      fileRegistry[file].content = gruntIsFile(file) ? gruntRead(file) + '\x0A' : '';
  }
docs: Read registered file's contents and store them into writeArray.
  
  @function readFile
  @param {String} file
  @return {String}
  @api private