Wording correction 8.8 release notes

Author: sspencerwire

docs/release_notes/8_8.md

@@ -116,7 +116,7 @@ The following performance monitoring tools have been updated:
 
 For details on changes in this category see the [upstream link here](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.8_release_notes/new-features#new-features-containers). Notable changes include:
 
-* The podman System Role is now available
+* The podman Linux System Roles are now available
 * Clients for sigstore signatures with Fulcio and Rekor are now available
 * Skopeo now supports generating sigstore key pairs
 * Podman now supports events for auditing