Combining several event modifiers in `hx-trigger` doesn't work correctly

Example:

```

Will only take care of `delay:100ms`, the `once` will be ignored. It's quite unclear how to achieve a combined result.

Start by reproducing the provided hx-trigger="load once delay:100ms" example with ws-send, then trace how hx-trigger modifiers are parsed and applied. Done means the same trigger honors both once and delay:100ms, with behavior verified against the example.

Written by the indexing model from the issue text.