spec: minor grammar fix
spec: minor grammar fix

Fixes #20830.

Change-Id: I18178064c955ad8d259df05ee954075ae42909b0
Reviewed-on: https://go-review.googlesource.com/47030
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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