doc: fix typo in dns docs

PR-URL: https://github.com/nodejs/node/pull/20711
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

doc/api/dns.md

@@ -66,7 +66,7 @@ An independent resolver for DNS requests.
 Note that creating a new resolver uses the default server settings. Setting
 the servers used for a resolver using
 [`resolver.setServers()`][`dns.setServers()`] does not affect
-other resolver:
+other resolvers:
 
 ```js
 const { Resolver } = require('dns');