acme/autocert: clarify that multiple names are allowed
acme/autocert: clarify that multiple names are allowed

Change-Id: Ib5111388859b36c1989aad1a1948bd83ab01b7e0
Reviewed-on: https://go-review.googlesource.com/132328
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/crypto,golang/crypto,golang/crypto