Adding comment to explain double-negative if condition

Author: eptekov

bin/ghe-backup

@@ -238,6 +238,9 @@ commands+=("
 echo \"$cmd_title\"
 ghe-backup-repositories || printf %s \"repositories \" >> \"$failures_file\"")
 
+# Pages backups are skipped only if GHE_BACKUP_PAGES is explicitly set to 'no' to guarantee backward compatibility.
+# If a customer upgrades backup-utils but keeps the config file from a previous version, Pages backups still work as expected.
+
 if [ "$GHE_BACKUP_PAGES" != "no" ]; then
   cmd_title=$(log_info "Backing up GitHub Pages artifacts ...")
   commands+=("