htmx-swapping and htmx-settling classes not added to OOB targets

[wnortje]

This may be related to #664.

I have a response that includes OOB elements. When the updates are made the target gets the htmx-swapping and htmx-settling classes applied as expected but the OOB elements do not get them. All elements are properly updated with their new content.

[benpate]

This is loosely related to the work on WebSockets, which uses OOB syntax when pushing freshly received messages into the DOM. Though it currently duplicates some of this logic, it would be awesome to expose this aspect of swapping so that (once changes are done here) WebSockets could inherit these updates, too.