Add doc section with DNS tunning (#2533)
Add doc section with DNS tunning (#2533)

* Add doc section with DNS tunning

* Typo fixed

hellysmile/aiohttp,arthurdarcet/aiohttp,rutsky/aiohttp,rutsky/aiohttp,KeepSafe/aiohttp,arthurdarcet/aiohttp,pfreixes/aiohttp,hellysmile/aiohttp,KeepSafe/aiohttp,arthurdarcet/aiohttp,rutsky/aiohttp,pfreixes/aiohttp,KeepSafe/aiohttp