issue-tracking.md - Don't mention CiviHR. There's nowhere to link.

The `HR` project in issues.civicrm.org was used for CiviHR 1.0-1.4.  When
the project was transferred to Compucorp, they moved issue-tracking to a
private system.  The JIRA `HR` project only exists for historical purposes.

docs/tools/issue-tracking.md

@@ -13,7 +13,6 @@ Used as an issue-tracking system for:
 
 * **[CiviCRM (Standard Repos)](https://issues.civicrm.org/jira/browse/CRM)**  (including `civicrm-core`, `civicrm-packages`, `civicrm-drupal`, `civicrm-joomla`, and `civicrm-wordpress`)
 * [CiviVolunteer](https://issues.civicrm.org/jira/browse/VOL)
-* [CiviHR](https://issues.civicrm.org/jira/browse/HR)
 * *...and a small number of [other projects](https://issues.civicrm.org/jira/secure/BrowseProjects.jspa?selectedCategory=all&selectedProjectType=all)*
 
 ### GitHub {:#github}