improve release message email

[ashwindasr]

To clarify the location of reference releases

[openshift-ci]

@ashwindasr: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/security	828cb8d	link	false	/test security

Full PR test history. Your PR dashboard.

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[joepvd]

/lgtm
/approve

May want https://issues.redhat.com/browse/ART-11382 later, but this is already an improvement.

[openshift-ci]

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