Add details tag to issue template

[StanFromIreland]

Closes #21133

We can also move "Perl Configuration" to the <summary> tag, but I think it is clearer like so.

The templates could also be updated to the .yml format and the comments would be much clearer.

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• This set of changes does not require a perldelta entry.

[khwilliamson]

This looks good to me, but I don't know very much about this. Is there a reason not to apply this now?

[guest20]

The main issue with these templates is that it's easy to ignore the you should fill in this instructions vs text that should be left in the template, and putting one inside a readmore is likely to reduce how often folks actually fill that in

[StanFromIreland]

Guest20s concern is more general from my understanding, and not limited to this change which will have little impact on that.

As for the concern, we could convert them to .yml format template which will make the comments more visible. See the cpython bug templates as an example.