New Rule: svelte/require-each-key

[baseballyama]

Motivation

This is exactly the same as Vue rule.
https://eslint.vuejs.org/rules/require-v-for-key.html

Description

Require key with {#each} syntax

Examples

<!-- ✓ GOOD -->
{#each items as item (item.id)}
  <li>{item.name} x {item.qty}</li>
{/each}

<!-- ✗ BAD -->
{#each items as item}
  <li>{item.name} x {item.qty}</li>
{/each}

Additional comments

No response