DEV: Enable and fix the 'require-iframe-title' lint

DEV: Enable and fix the ‘require-iframe-title’ lint

diff --git a/.template-lintrc.js b/.template-lintrc.js
index 994a145..344b969 100644
--- a/.template-lintrc.js
+++ b/.template-lintrc.js
@@ -31,6 +31,7 @@ module.exports = {
     "no-unnecessary-component-helper": true,
     "no-unused-block-params": true,
     "no-unbound": true,
+    "require-iframe-title": true,
     "self-closing-void-elements": true,
     "simple-unless": true,
     "style-concatenation": true,
diff --git a/app/assets/javascripts/admin/templates/email-preview-digest.hbs b/app/assets/javascripts/admin/templates/email-preview-digest.hbs
index 58733c1..0dfcb04 100644
--- a/app/assets/javascripts/admin/templates/email-preview-digest.hbs
+++ b/app/assets/javascripts/admin/templates/email-preview-digest.hbs
@@ -50,7 +50,7 @@
         {{#if htmlEmpty}}
           <p>{{i18n 'admin.email.no_result'}}</p>
         {{else}}
-          <iframe srcdoc={{model.html_content}} />
+          <iframe title={{i18n 'admin.email.html_preview'}} srcdoc={{model.html_content}} />
         {{/if}}
       {{else}}
         <pre>{{html-safe model.text_content}}</pre>
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 50f5134..f3ea234 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -3907,6 +3907,7 @@ en:
         format: "Format"
         html: "html"
         text: "text"
+        html_preview: "Email Content Preview"
         last_seen_user: "Last Seen User:"
         no_result: "No results found for summary."
         reply_key: "Reply Key"

GitHub sha: 07dc8d20

This commit appears in #9286 which was approved by eviltrout and jjaffeux. It was merged by riking.