all: upgrade go directive to at least 1.23.0 [generated]

By now Go 1.24.0 has been released, and Go 1.22 is no longer supported
per the Go Release Policy (https://go.dev/doc/devel/release#policy).

For golang/go#69095.

[git-generate]
(cd . && go get go@1.23.0 && go mod tidy && go fix ./... && go mod edit -toolchain=none)
(cd gopls/doc/assets && go get go@1.23.0 && go mod tidy && go fix ./... && go mod edit -toolchain=none)
(cd gopls && echo 'skipping because it already has go1.23.4 >= go1.23.0, nothing to do')

Change-Id: I37dad9abd1457a8a8aa940809b7ee6664fba006d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/649321
Auto-Submit: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

internal/jsonrpc2/serve_go116.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.16
-// +build go1.16
 
 package jsonrpc2
 

internal/jsonrpc2/serve_pre116.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !go1.16
-// +build !go1.16
 
 package jsonrpc2