Apply suggestions from code review

Co-Authored-By: Marcos Cáceres <[email protected]>

index.html

@@ -259,12 +259,12 @@ <h3>
         </pre>
         <div class="note" title="manifest.webmanifest or manifest.json?">
           The official file extension for the manifest is
-          <code>.webmanifest</code>. Some web servers recognize this extension
-          and transfer the file using the official <a>media type for a
-          manifest</a> (<code>application/manifest+json</code>). Developers can
-          also choose a different extension (e.g. <code>.json</code>) or none
-          at all (e.g. <code>/api/GetManifest</code>), but must make sure
-          that the manifest is transferred using the official media type.
+          `.webmanifest`. Some web servers recognize this extension
+          and transfer the file using the standardized <a>media type for a
+          manifest</a> (`application/manifest+json`). Developers can
+          also choose a different extension (e.g. `.json`) or none
+          at all (e.g. `/api/GetManifest`), but are strongly encouraged
+          that the manifest is transferred using the `application/manifest+json` media type.
         </div>
       </section>
     </section>