net/url: add examples for URL.Hostname and URL.RequestURI
net/url: add examples for URL.Hostname and URL.RequestURI

Change-Id: I72a10cd5dfb863f8219bb3b5b8280c017f523cf4
Reviewed-on: https://go-review.googlesource.com/42856
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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