cmd/go: add -v option in the usage section for get

Updates #23332

Change-Id: I964d36ed751ef1844ab6c40f61047297ff1443a3
Reviewed-on: https://go-review.googlesource.com/85797Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/go/alldocs.go

@@ -505,7 +505,7 @@
 //
 // Usage:
 //
-// 	go get [-d] [-f] [-fix] [-insecure] [-t] [-u] [build flags] [packages]
+// 	go get [-d] [-f] [-fix] [-insecure] [-t] [-u] [-v] [build flags] [packages]
 //
 // Get downloads the packages named by the import paths, along with their
 // dependencies. It then installs the named packages, like 'go install'.

src/cmd/go/internal/get/get.go

@@ -22,7 +22,7 @@ import (
 )
 
 var CmdGet = &base.Command{
-	UsageLine: "get [-d] [-f] [-fix] [-insecure] [-t] [-u] [build flags] [packages]",
+	UsageLine: "get [-d] [-f] [-fix] [-insecure] [-t] [-u] [-v] [build flags] [packages]",
 	Short:     "download and install packages and dependencies",
 	Long: `
 Get downloads the packages named by the import paths, along with their