docs: [#379] review User Guide

Author: josecelano

docs/user_guide.md

@@ -4,9 +4,9 @@
 
 There are only three roles:
 
-- Guest: unauthenticated user.
-- User: authenticated user.
-- Admin: authenticated user with admin privileges.
+- `Guest`: unauthenticated user.
+- `User`: authenticated user.
+- `Admin`: authenticated user with admin privileges.
 
 > **NOTICE**: there is only one "admin" and it's the account of the first registered user.
 
@@ -22,17 +22,22 @@ You can add a PNG image with:
 ![alternative description for the image](https://raw.githubusercontent.com/torrust/torrust-index-gui/develop/docs/media/torrust_logo.png)
 ```
 
-The image will be proxied by the backend. This means that the image will be downloaded by the backend and served by the backend itself. The backend will cache the image but
-you have to make sure that the image is available at the URL you provided.
+The image will be proxied by the backend. This means that the image will be downloaded by the backend and served by the backend itself. The backend will cache the image but you have to make sure that the image is available at the URL you provided.
 
 ## Categories
 
 Torrents can have only one category. You have to assign a category to your torrent when you upload it.
 
-If the "admin" deletes the category sued by a torrent, the torrent category will be set to `null`.
+If the "admin" deletes the category used by a torrent, the torrent category will be set to `null`.
 
 ## Tags
 
 Torrents can have multiple tags. You can assign tags to your torrent when you upload it. Tags are created by the "admin" and users can only choose from the existing tags.
 
 If the "admin" deletes a tag, the tag will be removed from all the torrents that use it.
+
+## Notes
+
+- The application does not support [BitTorrent Version 2][BEP_52].
+
+[BEP_52]: https://www.bittorrent.org/beps/bep_0052.html