Rule proposal: no-computed-after-await

[cjpearson]

Please describe what the rule should do:

Disallow asynchronously registered watch

What category should the rule belong to?

[ ] Enforces code style (layout)
[X] Warns about a potential error (problem)
[ ] Suggests an alternate way of doing something (suggestion)
[ ] Other (please specify:)

<script>
import { computed } from 'vue'
export default {
  async setup() {
    /* ✓ GOOD */
    computed(() => { /* ... */ })

    await doSomething()

    /* ✗ BAD */
    computed(() => { /* ... */ })
  }
}
</script>

Additional context

This rule is based on no-watch-after-await. According to the documentation, watch and computed must be called synchronously in order for them to be properly cleaned up. There is currently the no-watch-after-await rule to catch asynchronous calls of watch, but no comparable rule for computed.

[waynzh]

Before this rule gets adopted, you could use no-restricted-call-after-await as a temporary workaround:

"vue/no-restricted-call-after-await": ["error",
    { "module": "vue", "path": "computed" },
  ]