net/http: update sanitizeCookieValue description
net/http: update sanitizeCookieValue description

Commit 8f6d68eb (CL 37328) changed the code of sanitizeCookieValue without updating its description.

Change-Id: Ib4a1a1f316548258b828458a31b09706bbd59b53
GitHub-Last-Rev: 9731494e177d909f33dd7d5ecfe1fd1a1c88a3e1
GitHub-Pull-Request: golang/go#34790
Reviewed-on: https://go-review.googlesource.com/c/go/+/200041
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

cloudflare/go,akutz/go,golang/go,golang/go,CAFxX/go,akutz/go,nawawi/go,golang/go,golang/go,nawawi/go,CAFxX/go,akutz/go,nawawi/go,golang/go,cloudflare/go,cloudflare/go,CAFxX/go,cloudflare/go,akutz/go,cloudflare/go,akutz/go,nawawi/go,akutz/go,akutz/go,CAFxX/go,golang/go,CAFxX/go,nawawi/go,CAFxX/go,cloudflare/go,nawawi/go,CAFxX/go,CAFxX/go,cloudflare/go,akutz/go,golang/go,nawawi/go,cloudflare/go,golang/go,nawawi/go