fmt: remove unnecessary trailing commas in doc.go
fmt: remove unnecessary trailing commas in doc.go

Change-Id: Ib5efe172c55ff624b6771c2f02c466e35ba6cc50
Reviewed-on: https://go-review.googlesource.com/45090
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

nawawi/go,josharian/go,josharian/go,nawawi/go,golang/go,polyverse-security/go,cloudflare/go,akutz/go,polyverse-security/go,vsekhar/elastic-go,vsekhar/elastic-go,akutz/go,akutz/go,CAFxX/go,nawawi/go,codestation/go,golang/go,codestation/go,codestation/go,cloudflare/go,Cofyc/go,codestation/go,codestation/go,akutz/go,codestation/go,nawawi/go,cloudflare/go,josharian/go,christopher-henderson/Go,Cofyc/go,codestation/go,polyverse-security/go,cloudflare/go,josharian/go,Cofyc/go,nawawi/go,cloudflare/go,vsekhar/elastic-go,Cofyc/go,CAFxX/go,CAFxX/go,golang/go,polyverse-security/go,polyverse-security/go,vsekhar/elastic-go,vsekhar/elastic-go,nawawi/go,cloudflare/go,golang/go,CAFxX/go,akutz/go,vsekhar/elastic-go,akutz/go,josharian/go,polyverse-security/go,golang/go,CAFxX/go,akutz/go,codestation/go,golang/go,Cofyc/go,CAFxX/go,josharian/go,cloudflare/go,Cofyc/go,vsekhar/elastic-go,polyverse-security/go,vsekhar/elastic-go,nawawi/go,CAFxX/go,Cofyc/go,nawawi/go,CAFxX/go,golang/go,josharian/go,akutz/go,golang/go,Cofyc/go,polyverse-security/go,cloudflare/go,josharian/go