Docs: use try/finally to always release the client

[stefee]

Use try/finally to always release the client on error before handling

Refs: https://node-postgres.com/features/pooling#examples

// async/await - check out a client
;(async () => {
  const client = await pool.connect()
  try {
    const res = await client.query('SELECT * FROM users WHERE id = $1', [1])
    console.log(res.rows[0])
  } finally {
    // Make sure to release the client before any error handling,
    // just in case the error handling itself throws an error.
    client.release()
  }
})().catch(err => console.log(err.stack))

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]

LGTM

[mcollina]

lgtm