cylc config shows unhelpful information for xtriggers

[ColemanTom]

Description

If you have an xtrigger and run cylc config my_workflow the xtrigger is listed as ... = [xtrigger-func cmd] which isn't very informative or helpful.

Reproducible Example

I just used the test case from the xtrigger plugin PR.

Results was

$ cylc config cylctb-20231206T033820Z-uOHK/f/xtriggers/04-respect-cylc-pythonpath
[scheduler]
    cycle point format = %Y
[scheduling]
    initial cycle point = 2010
    final cycle point = 2011
    [[xtriggers]]
        x1 = [xtrigger-func cmd]
    [[graph]]

Expected Behaviour

A resolved string of what the xtrigger was for reference after templating is resolved.