Release notes: Transaction Monitoring - Technical preview - fix

By issue https://issues.jboss.org/browse/EAP7-192 there was added two new transactional statistics to TM. Those two should be mentioned as technical preview in release notes. Accessible only via JMX.

In release notes version 8129613 the text on Transactional monitoring is wrong. All discussed with dmichael in comments
https://issues.jboss.org/browse/EAP7-192?focusedCommentId=13200777#comment-13200777
https://issues.jboss.org/browse/EAP7-192?focusedCommentId=13200799#comment-13200799

This jira serves to tracking if requested changes were put to Release Notes guide for EAP 7.0.0 GA (MR already exists, see EAP7-192)
This is created as a Blocker jira as the release notes are with current text inconsistent with Development guide as one talks about supported feature (transaction monitoring) and other (release notes) talks about technical preview.