Please describe what the rule should do:

The rule should warn when a custom directive is used, but not imported. The rule should also accept some kind of ignore option to avoid false positives with globally-registered custom directives.

What category should the rule belong to?

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

Provide 2-3 code examples that this rule should warn about:

Should warn on:

<template> <input v-focus> </template> <script setup> // vFocus is not imported or defined anywhere </script>

<template> <a v-sref="someValue"> <!-- anchor contents --> </a> </template> <script setup> // vSref is not imported or defined anywhere </script>

Should not warn on:

<template> <input v-focus> </template> <script setup> import vFocus from '../path/to/vFocus'; </script>

<template> <a v-sref="someValue"> <!-- anchor contents --> </a> </template> <script setup> import vSref from '../path/to/vSref'; </script>

Additional context

There is a runtime warning in the browser console, but it would be cool if we can catch these issues when linting too.

[Vue warn]: Failed to resolve directive: sref