cmd/go: explain fmt, fix, vet a bit more in go help

Fixes #20918.

Change-Id: I84306242084631bbe7a9adc839f92e72ac1a3e75
Reviewed-on: https://go-review.googlesource.com/73331
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/go/alldocs.go

@@ -18,8 +18,8 @@
 // 	doc         show documentation for package or symbol
 // 	env         print Go environment information
 // 	bug         start a bug report
-// 	fix         run go tool fix on packages
-// 	fmt         run gofmt on package sources
+// 	fix         update packages to use new APIs
+// 	fmt         gofmt (reformat) package sources
 // 	generate    generate Go files by processing source
 // 	get         download and install packages and dependencies
 // 	install     compile and install packages and dependencies
@@ -28,7 +28,7 @@
 // 	test        test packages
 // 	tool        run specified go tool
 // 	version     print Go version
-// 	vet         run go tool vet on packages
+// 	vet         report likely mistakes in packages
 //
 // Use "go help [command]" for more information about a command.
 //
@@ -339,7 +339,7 @@
 // The report includes useful system information.
 //
 //
-// Run go tool fix on packages
+// Update packages to use new APIs
 //
 // Usage:
 //
@@ -355,7 +355,7 @@
 // See also: go fmt, go vet.
 //
 //
-// Run gofmt on package sources
+// Gofmt (reformat) package sources
 //
 // Usage:
 //
@@ -794,7 +794,7 @@
 // Version prints the Go version, as reported by runtime.Version.
 //
 //
-// Run go tool vet on packages
+// Report likely mistakes in packages
 //
 // Usage:
 //

src/cmd/go/internal/fix/fix.go

@@ -15,7 +15,7 @@ import (
 var CmdFix = &base.Command{
 	Run:       runFix,
 	UsageLine: "fix [packages]",
-	Short:     "run go tool fix on packages",
+	Short:     "update packages to use new APIs",
 	Long: `
 Fix runs the Go fix command on the packages named by the import paths.
 

src/cmd/go/internal/fmtcmd/fmt.go

@@ -24,7 +24,7 @@ func init() {
 var CmdFmt = &base.Command{
 	Run:       runFmt,
 	UsageLine: "fmt [-n] [-x] [packages]",
-	Short:     "run gofmt on package sources",
+	Short:     "gofmt (reformat) package sources",
 	Long: `
 Fmt runs the command 'gofmt -l -w' on the packages named
 by the import paths. It prints the names of the files that are modified.

src/cmd/go/internal/vet/vet.go

@@ -18,7 +18,7 @@ var CmdVet = &base.Command{
 	Run:         runVet,
 	CustomFlags: true,
 	UsageLine:   "vet [-n] [-x] [build flags] [vet flags] [packages]",
-	Short:       "run go tool vet on packages",
+	Short:       "report likely mistakes in packages",
 	Long: `
 Vet runs the Go vet command on the packages named by the import paths.