📝 Fix form for the FastAPI and friends newsletter (#9749)

docs/en/docs/newsletter.md

@@ -1,5 +1,5 @@
 # FastAPI and friends newsletter
 
-<iframe class="mj-w-res-iframe" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="https://app.mailjet.com/widget/iframe/6gQ4/GDo" width="100%"></iframe>
+<iframe data-w-type="embedded" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="https://xr4n4.mjt.lu/wgt/xr4n4/hj5/form?c=40a44fa4" width="100%" style="height: 0;"></iframe>
 
-<script type="text/javascript" src="https://app.mailjet.com/statics/js/iframeResizer.min.js"></script>
+<script type="text/javascript" src="https://app.mailjet.com/pas-nc-embedded-v1.js"></script>

docs/en/mkdocs.yml

@@ -165,6 +165,7 @@ nav:
 - external-links.md
 - benchmarks.md
 - help-fastapi.md
+- newsletter.md
 - contributing.md
 - release-notes.md
 markdown_extensions: