function sendEquipmentRequestCompletedEmail_(request) {
  let template = HtmlService.createTemplateFromFile('request-complete.html');
  template.request = request;
  let msg = template.evaluate();
  MailApp.sendEmail({
    to: request.email,
    subject: 'Equipment request completed',
    htmlBody: msg.getContent(),
  });
}
Sends an email notifying the requestor that the request is complete.

@param {Object} request - Request details