Add missing check Rake tasks

doc/administration/raketasks/check.md

@@ -7,6 +7,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 # Integrity check Rake task **(FREE SELF)**
 
 GitLab provides Rake tasks to check the integrity of various components.
+See also the [check GitLab configuration Rake task](maintenance.md#check-gitlab-configuration).
 
 ## Repository integrity
 

doc/administration/raketasks/maintenance.md

@@ -106,6 +106,8 @@ The `gitlab:check` Rake task runs the following Rake tasks:
 - `gitlab:gitlab_shell:check`
 - `gitlab:gitaly:check`
 - `gitlab:sidekiq:check`
+- `gitlab:incoming_email:check`
+- `gitlab:ldap:check`
 - `gitlab:app:check`
 
 It checks that each component was set up according to the installation guide and suggest fixes