Shorthand for propagating events

[Rich-Harris]

This has come up once or twice — since component events don't propagate (unlike DOM events), if you want to listen to an event coming from a deeply nested component you have to propagate the event manually, like so:

<IntermediateComponent on:foo='fire("foo",event)'/>

I don't think we should automatically bubble events, since that's a potential source of confusion and would mean adding annoying extra code to every component that had nested components. But we could make it a bit less burdensome to manually propagate events with a shorthand syntax:

<IntermediateComponent on:foo/>

[stalkerg]

It's a good idea! But also I want to see shorthand syntax for preventDefault(). Like:

<a href="" on:default:click="set({svelte: 'perfect'})">link</a>

[Rich-Harris]

Added in 1.27