feat: add actionResult option in handle hook to change form result

[qurafi]

Closes #9676

Allow users to return form action result from handle hook using:resolve(event, {actionResult: ...})

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Latest commit: ca47229

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[Rich-Harris]

Thank you for the PR. I don't think this is the way to go though — as far as I can see this doesn't give you a way to replace form but not to modify/inspect it, which doesn't seem all that flexible. I think it's much more likely that if we were to add a feature like this, we'd have something like a handleAction hook, similar to the proposed handleLoad hook in #9542.

On a process note, the PR template includes the following:

It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs

The key word here is 'discussed' — merely opening an issue doesn't qualify :) PRs for new features like this are much more likely to be merged if they're the result of a conversation about how they should be designed! As things stand I'm not really sure what the purpose of this feature is, so I'm going to close this and ask for clarification on #9676.