crypto: add import comments.

Change-Id: I33240faf1b8620d0cd600de661928d8e422ebdbc
Reviewed-on: https://go-review.googlesource.com/1235
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/util.go b/util.go
index 0763c9a..598e3df 100644
--- a/util.go
+++ b/util.go
@@ -14,7 +14,7 @@
 // 	        panic(err)
 // 	}
 // 	defer terminal.Restore(0, oldState)
-package terminal
+package terminal // import "golang.org/x/crypto/ssh/terminal"
 
 import (
 	"io"