go/analysis/passes/modernize: document 'go fix' command

Update the modernizer docs to recommend go fix in preference
to the the multichecker-based modernize command.

Also, delete the gopls/internal/analysis/modernize/cmd/modernize
command, which is internal and deprecated. This will break
'go run .../modernize@latest' at the next gopls release.

Fixes golang/go#80510

Change-Id: I5b27787b3afdaf86c5c1222b3cc02ab45c138a38
Reviewed-on: https://go-review.googlesource.com/c/tools/+/804000
Auto-Submit: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Hongxiang Jiang <hxjiang@golang.org>
diff --git a/go/analysis/passes/modernize/doc.go b/go/analysis/passes/modernize/doc.go
index bf83de3..e441f8d 100644
--- a/go/analysis/passes/modernize/doc.go
+++ b/go/analysis/passes/modernize/doc.go
@@ -15,13 +15,16 @@
 trivial to fix. We regard any modernizer whose fix changes program
 behavior to have a serious bug and will endeavor to fix it.
 
-To apply all modernization fixes en masse, you can use the
+Since Go 1.26, the 'go fix' command has included the modernize suite,
+so to apply all modernization fixes en masse, you can use the
 following command:
 
-	$ go run golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize@latest -fix ./...
+	$ go fix ./...
 
-(Do not use "go get -tool" to add gopls as a dependency of your
-module; gopls commands must be built from their release branch.)
+If you need to run a modernizer added or modified since the Go
+release, you can use this standalone command:
+
+	$ go run golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize@latest -fix ./...
 
 If the tool warns of conflicting fixes, you may need to run it more
 than once until it has applied all fixes cleanly. This command is
diff --git a/gopls/internal/analysis/modernize/cmd/modernize/main.go b/gopls/internal/analysis/modernize/cmd/modernize/main.go
deleted file mode 100644
index 0f1f5e6..0000000
--- a/gopls/internal/analysis/modernize/cmd/modernize/main.go
+++ /dev/null
@@ -1,21 +0,0 @@
-// Copyright 2024 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// The modernize command suggests (or, with -fix, applies) fixes that
-// clarify Go code by using more modern features.
-//
-// See [golang.org/x/tools/go/analysis/passes/modernize] for details.
-//
-// Deprecated: use 'go run
-// golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize' instead. In
-// due course the modernizer suite will be accessed through "go fix";
-// see https://go.dev/issue/71859.
-package main
-
-import (
-	"golang.org/x/tools/go/analysis/multichecker"
-	"golang.org/x/tools/go/analysis/passes/modernize"
-)
-
-func main() { multichecker.Main(modernize.Suite...) }