net/http: http.Request.Context doc fix
net/http: http.Request.Context doc fix

The comment on http.Request.Context says that the context
is canceled when the client's connection closes even though
this has not been implemented. See #15927

Change-Id: I50b68638303dafd70f77f8f778e6caff102d3350
Reviewed-on: https://go-review.googlesource.com/23672
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

nawawi/go,suncycheng/go,golang/go,CAFxX/go,vsekhar/elastic-go,vsekhar/elastic-go,polyverse-security/go,suncycheng/go,4ad/go,Cofyc/go,cloudflare/go,derekmarcotte/go,goodlang/good,theif519/go,derekmarcotte/go,golang/go,josharian/go,josharian/go,akutz/go,CAFxX/go,goodlang/good,CAFxX/go,cloudflare/go,vsekhar/elastic-go,josharian/go,4ad/go,akutz/go,golang/go,4ad/go,goodlang/good,josharian/go,goodlang/good,linux-on-ibm-z/go,josharian/go,ImJasonH/go,4ad/go,4ad/go,cloudflare/go,Cofyc/go,vsekhar/elastic-go,nawawi/go,polyverse-security/go,Cofyc/go,akutz/go,ImJasonH/go,polyverse-security/go,momchil-velikov/go,linux-on-ibm-z/go,momchil-velikov/go,golang/go,ImJasonH/go,golang/go,linux-on-ibm-z/go,4ad/go,codestation/go,nawawi/go,CAFxX/go,vsekhar/elastic-go,ImJasonH/go,suncycheng/go,codestation/go,akutz/go,momchil-velikov/go,ImJasonH/go,akutz/go,suncycheng/go,CAFxX/go,josharian/go,theif519/go,polyverse-security/go,goodlang/good,josharian/go,momchil-velikov/go,momchil-velikov/go,theif519/go,cloudflare/go,akutz/go,polyverse-security/go,suncycheng/go,momchil-velikov/go,theif519/go,4ad/go,goodlang/good,derekmarcotte/go,polyverse-security/go,vsekhar/elastic-go,polyverse-security/go,codestation/go,codestation/go,derekmarcotte/go,ImJasonH/go,linux-on-ibm-z/go,josharian/go,momchil-velikov/go,linux-on-ibm-z/go,nawawi/go,linux-on-ibm-z/go,cloudflare/go,theif519/go,derekmarcotte/go,CAFxX/go,christopher-henderson/Go,derekmarcotte/go,suncycheng/go,codestation/go,suncycheng/go,golang/go,akutz/go,vsekhar/elastic-go,linux-on-ibm-z/go,vsekhar/elastic-go,cloudflare/go,nawawi/go,goodlang/good,nawawi/go,momchil-velikov/go,4ad/go,akutz/go,Cofyc/go,polyverse-security/go,Cofyc/go,codestation/go,ImJasonH/go,codestation/go,theif519/go,goodlang/good,CAFxX/go,Cofyc/go,ImJasonH/go,cloudflare/go,nawawi/go,Cofyc/go,theif519/go,golang/go,derekmarcotte/go,golang/go,suncycheng/go,CAFxX/go,cloudflare/go,nawawi/go,linux-on-ibm-z/go,Cofyc/go,codestation/go,theif519/go,derekmarcotte/go