renderToPipeableStream: Expose errors through onError, no longer emit un-catchable error event on internal stream

[f0x52]

Fixes #404

Changes error and abort handling in renderToPipeableStream so the stream no longer emits an uncatchable error event. Instead errors are passed to options.onError if provided. If there is no error callback it's rethrown, though maybe that's not ideal since it happens in the async chain, so can't really be caught either. Alternatively this could just console.error, so it doesn't get silently swallowed entirely?

Also added an optional reason argument for stream.abort(), defaulting to new Error(The render was aborted by the server without a reason.) inspired by React. Previously this was just new Error('aborted'), though this was never exposed to consumers.
Abort still destroys the stream, and also calls the onError callback (if defined) with the reason

[changeset-bot]

🦋 Changeset detected

Latest commit: 310e1bb

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
preact-render-to-string	Patch

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