cmd/go: Update alldocs.go header to point to the correct shell script.

The script was renamed in b3000b6f.

Change-Id: I45ecafff7400e4bff14f31906278609abf2bcb9f
Reviewed-on: https://go-review.googlesource.com/9667Reviewed-by: Andrew Gerrand <adg@golang.org>

src/cmd/go/alldocs.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// DO NOT EDIT THIS FILE. GENERATED BY mkdoc.sh.
-// Edit the documentation in other files and rerun mkdoc.sh to generate this one.
+// DO NOT EDIT THIS FILE. GENERATED BY mkalldocs.sh.
+// Edit the documentation in other files and rerun mkalldocs.sh to generate this one.
 
 /*
 Go is a tool for managing Go source code.

src/cmd/go/main.go

@@ -214,8 +214,8 @@ var documentationTemplate = `// Copyright 2011 The Go Authors.  All rights reser
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// DO NOT EDIT THIS FILE. GENERATED BY mkdoc.sh.
-// Edit the documentation in other files and rerun mkdoc.sh to generate this one.
+// DO NOT EDIT THIS FILE. GENERATED BY mkalldocs.sh.
+// Edit the documentation in other files and rerun mkalldocs.sh to generate this one.
 
 /*
 {{range .}}{{if .Short}}{{.Short | capitalize}}