Fixed code example of type usage docs

[recloud-dev]

No description provided.

[chandr-andr]

@recloud-dev Hello!
Thank you very much for your contribution.
What do you think about changing this

connection = await db_pool.connection()
await connection.execute(...)
await connection.close()

to this variant:

async with db_pool.acquire() as conn:
	await conn.execute(...)

Usually, it's better to let the context manager do all the work.

[recloud-dev]

Yep, it's better this way, I'll make a replacement.

[chandr-andr]

LGTM