message: Switch a let to a const
  As suggested in:
diff: @@ -24,9 +24,8 @@ const CUSTOM_VALIDATION_RULES_MODULE_PATH = 'custom-validation-rules';
  */
  export function findGraphQLConfigDir(dirPath: Uri): ?string {
  let currentPath = path.resolve(dirPath);
  - let filePath;
  while (true) {
  - filePath = path.join(currentPath, '.graphqlrc');
  + const filePath = path.join(currentPath, '.graphqlrc');
  if (fs.existsSync(filePath)) {
  break;
  }
  