doc: fix typo e.g., => e.g.

Fixes: nodejs/code-and-learn#58
PR-URL: #9563
Reviewed-By: Yosuke Furukawa <[email protected]>
Reviewed-By: Roman Reiss <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Shigeki Ohtsu <[email protected]>

Author: dorako321

doc/api/dns.md

@@ -256,7 +256,7 @@ added: v0.1.90
 Uses the DNS protocol to resolve name server records (`NS` records) for the
 `hostname`. The `addresses` argument passed to the `callback` function will
 contain an array of name server records available for `hostname`
-(e.g., `['ns1.example.com', 'ns2.example.com']`).
+(e.g. `['ns1.example.com', 'ns2.example.com']`).
 
 ## dns.resolveSoa(hostname, callback)
 <!-- YAML