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`
@@ -73,4 +73,4 @@ need to [add your certificate to GitLab's trusted certificates](https://docs.git
 If it's an issue with GitLab not trusting connections to Slack, then the GitLab
 OpenSSL trust store probably got messed up somehow. Typically this is from overriding
 the trust store with `gitlab_rails['env'] = {"SSL_CERT_FILE" => "/path/to/file.pem"}`
-or by accidentally modifying the default CA bundle `/opt/gitlab/embedded/ssl/certs/cacert.pem`.
\ No newline at end of file
+or by accidentally modifying the default CA bundle `/opt/gitlab/embedded/ssl/certs/cacert.pem`.