Govern: Security Policies Group documentation updates

Please be sure to double-check the file for any other version mentions as vale can miss.

Once a merge request is created link it to this issue. Note - only 1 merge request per issue to reduce the overhead as the technical writing team needs to review all changes.

Affected files:

 gitlab/doc/user/application_security/policies/index.md
 13:82   suggestion  If possible, remove the reference to 'GitLab 14.'.  gitlab.OutdatedVersions 
 264:72  suggestion  If possible, remove the reference to 'GitLab 13.'.  gitlab.OutdatedVersions 


 gitlab/doc/user/application_security/policies/scan-result-policies.md
 66:82  suggestion  If possible, remove the reference to 'GitLab 14.'.  gitlab.OutdatedVersions 

✔ 0 errors, 0 warnings and 3 suggestions in 6 files.