Revert "docs(client-aborted): remove deprecated function (#4898)"

[climba03003]

This reverts commit cc347d7.

The author on #4898 do not test if request.aborted is really identical to request.destoryed.
Instead, they are two completely different property and the meaning is different.

For request.destoryed, Node.js document is telling us to Check but not Use as replacement.

From the below example, a properly closed connection would also triggered when using request.destroyed.
So, it is not meaning request abort.

test('onRequestAbort should not be called when using destroyed', t => {
  const fastify = Fastify()

  t.plan(3)
  t.teardown(() => fastify.close())

  fastify.addHook('onRequestAbort', async function (req) {
    process.nextTick(() => t.fail())
  })

  fastify.route({
    method: 'GET',
    path: '/',
    async handler (request, reply) {
      return { hello: 'world' }
    }
  })

  fastify.listen({ port: 0 }, (err, address) => {
    t.error(err)

    sget({
      method: 'GET',
      url: address
    }, (err, response, body) => {
      t.error(err)
      t.equal(response.statusCode, 200)
    })
  })
})

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[Fdawgs]

Thanks @climba03003