Fix broken docs link

doc/user/project/integrations/slack.md

@@ -28,13 +28,13 @@ Your Slack team will now start receiving GitLab event notifications as configure
 ## Troubleshooting
 
 If you're having trouble with the Slack integration not working, then start by
-searching through the [Sidekiq logs](/doc/administration/logs.md#sidekiqlog)
+searching through the [Sidekiq logs](../../../administration/logs.md#sidekiqlog)
 for errors relating to your Slack service.
 
 ### Something went wrong on our end
 
 This is a generic error shown in the GitLab UI and doesn't mean much by itself.
-You'll need to look in [the logs](/doc/administration/logs.md#productionlog) to find
+You'll need to look in [the logs](../../../administration/logs.md#productionlog) to find
 an error message and keep troubleshooting from there.
 
 ### `certificate verify failed`