html/template: mention risks of the CSS, HTML, JS, etc. types
html/template: mention risks of the CSS, HTML, JS, etc. types

Fixes #15399

Change-Id: I5b9645cb9ddede6981ce0a005e0c6fdd8a751c6f
Reviewed-on: https://go-review.googlesource.com/22824
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Reviewed-by: Minux Ma <72d850dbd8858b791995463d8539b5a379577f28@golang.org>
Reviewed-by: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

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