move hx-trigger response header timing to after swap

[MichaelWest22]

Description

we removed the hx-trigger-after-swap and hx-trigger-after-settle response headers as having 3 of the same thing is not really justified. Now in htmx4 settle delay defaults to 1ms and swap normally happens straight away. Since we now how only one hx-trigger to simplify things I tihnk it is better to move the triggering to after the request completes. I've moved it to the finally stage so it triggers even if hx-location etc fires. By having it trigger after the swap at the end we can cover the use cases for the old after-swap and after-settle with this one header and the only downside is you can't fire the manual trigger before the swap happens. But in practice there is little need for a before swap trigger as the only reason to need this is to perform a custom action before removing some content with a swap and this kind of action would be much easier to be performed with a client side event listener for a htmx:before:swap type event rather than a hx-trigger header.

With this change all users who had after triggers can just move to using the single hx-trigger hopefully.

Corresponding issue:

Testing

moved one test

Checklist

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• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded