Replace he/she with they to be more inclusive

Author: Raphaëll Roussel

templates/blog/post_show.html.twig

@@ -16,8 +16,8 @@
 
     <div id="post-add-comment" class="well">
         {# The 'IS_AUTHENTICATED_FULLY' role ensures that the user has entered
-        his/her credentials (login + password) during this session. If he/she
-        is automatically logged via the 'Remember Me' functionality, he/she won't
+        their credentials (login + password) during this session. If they
+        are automatically logged via the 'Remember Me' functionality, they won't
         be able to add a comment.
         See https://symfony.com/doc/current/security/remember_me.html#forcing-the-user-to-re-authenticate-before-accessing-certain-resources
         #}