* Create expressions.md

* Update queries.md

* Update expressions.md

* Update whats-new-in-v7-4.md

* remove alerting NG references and alerting examples

* Update docs/sources/panels/expressions.md

* Update docs/sources/panels/expressions.md

* remove empty line

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

Co-authored-by: kyle <kyle@grafana.com>