message: Fix a bug where cite and ref won't autocomplete
diff: @@ -17,8 +17,8 @@ export class LaTeXCompletionItemProvider implements vscode.CompletionItemProvide
  var command_reg = /\\(.*?){/.exec(line.substring(command_idx));
  var command;
  var is_cite = false;
  - if (command_reg != null) {
  - command = command[1];
  + if (command_reg != undefined) {
  + command = command_reg[1];
  is_cite = command.indexOf('cite') > -1;
  }
  if (line.slice(-1) == ',' && !is_cite) {
  