Update pull_request_template.md (#258)

Rewording the "related issues" comments

.github/pull_request_template.md

@@ -1,8 +1,9 @@
 # rocprofiler-systems Pull Request
 
 ## Related Issue
-<!-- Please link to the issue(s) that this PR addresses.  -->
-- [ ] Closes #<issue number or link>
+<!-- Please link to the external GitHub issue(s) that this PR addresses. 
+  If providing a JIRA ticket, please don't include an internal link -->
+- [ ] Closes #<issue number>
 
 ## What type of PR is this? (check all that apply)