message: Add printer cases for TS{Object,Symbol}Keyword and TSThisType.
diff: @@ -1688,18 +1688,27 @@ function genericPrintNoParens(path, options, print) {
  case "TSNumberKeyword":
  return fromString("number", options);
  + case "TSObjectKeyword":
  + return fromString("object", options);
  +
  case "TSBooleanKeyword":
  return fromString("boolean", options);
  case "TSStringKeyword":
  return fromString("string", options);
  + case "TSSymbolKeyword":
  + return fromString("symbol", options);
  +
  case "TSAnyKeyword":
  return fromString("any", options);
  case "TSVoidKeyword":
  return fromString("void", options);
  + case "TSThisType":
  + return fromString("this", options);
  +
  case "TSNullKeyword":
  return fromString("null", options);
  