add tidbit about when jira tickets are auto-created (quick win) (#1962)

* add tidbit about when findings are created

* Update docs/semgrep-appsec-platform/jira.md

Co-authored-by: Katie Horne <[email protected]>

* emphasis

---------

Co-authored-by: Katie Horne <[email protected]>

Author: s-santillan

docs/semgrep-appsec-platform/jira.md

@@ -29,6 +29,7 @@ The Semgrep Jira integration provides the following capabilities:
 - You can automate the creation of tickets for high severity, high confidence findings in your [default branch](/deployment/add-semgrep-to-ci#default-branch-names).
   - Automated ticket creation can be configured on a per-product setting.
   - For Supply Chain findings, tickets are created for reachable findings.
+  - Tickets are automatically created for **new** findings generated by scans that occur **after** enabling automated ticket creation. Tickets are not automatically created for existing findings.
 - Tickets can be created in **multiple Jira projects** if manually specified at ticket creation time.