Added SendGrid Documentation

docs/content/add-plugins/sendgrid.md

@@ -1,9 +0,0 @@
-# SendGrid (Documentation coming soon)
-
-[View plugin here](https://github.com/medusajs/medusa/tree/master/packages/medusa-plugin-sendgrid)
-
-<div>
-  <video width="100%" height="100%" playsinline autoplay muted controls>
-    <source src="https://user-images.githubusercontent.com/59018053/154807282-1e72671f-1936-411d-b914-e05c6597693a.mp4" type="video/mp4" />
-  </video>
-</div>

www/docs/src/css/custom.css

@@ -255,3 +255,7 @@ footer {
 .prism-code div:active {
   outline: none !important;
 }
+
+details summary {
+  cursor: pointer;
+}