* add note that it's not supported to repeat a panel zero times
see https://github.com/grafana/grafana/issues/23036#issuecomment-603479142

Signed-off-by: David Ellis <ellisda@gmail.com>

* Update docs/sources/reference/templating.md

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