Missing bracket

doc/EN/apps.org

@@ -135,7 +135,7 @@ The black hole for web adverts. Block adverts at the domain name level within yo
 * PostActiv
 An alternative federated social networking system compatible with GNU Social, Pleroma and Mastodon. It includes some optimisations and fixes currently not available within the main GNU Social project.
 
-[[./app_postactiv.html][How to use it]
+[[./app_postactiv.html][How to use it]]
 * PrivateBin
 A pastebin where the server has zero knowledge of the content being pasted.