function displayTokens(tokens, parentEl) {
  const tokensDiv = document.createElement('div');
  tokensDiv.classList = `tokens`;
  tokensDiv.innerHTML =
      tokens.map(token => `<div class="token">${token}</div>`).join('\n');
  parentEl.appendChild(tokensDiv);
}
Render the tokens.

@param {string[]} tokens tokens to display
@param {HTMLElement} parentEl parent element