fix bad copy/paste of slack settings description

app/views/admin/application_settings/show.html.haml

@@ -370,7 +370,7 @@
       %button.btn.js-settings-toggle{ type: 'button' }
         = expanded ? 'Collapse' : 'Expand'
       %p
-        = _('Geo allows you to replicate your GitLab instance to other geographical locations.')
+        = _('Slack integration allows you to interact with GitLab via shash commands in a chat window.')
     .settings-content
       = render partial: 'slack'