various: Remove legacy "+build" comments

Go 1.17 and earlier used a different syntax for build constraint comments,
starting with "+build". Go 1.18 changed this to the modern "go:build" form
as part of standardizing the structure of toolchain directive comments,
and so for a while it was convention to include comments in both styles
to allow building with both old and new Go compilers.

However, Go 1.17 is no longer supported, and regardless of that we only
expect OpenTofu to be built with the specific version we have selected
in "go.mod" and ".go-version" anyway, so we no longer need the legacy form
of these comments: the all supported Go toolchains now support the new
form, which this commit retains.

golangci-lint v2.6.0 includes a check for this legacy form, so removing
this will also allow us to upgrade to a newer version of that linter
aggregator in a future commit.

Signed-off-by: Martin Atkins <mart@degeneration.co.uk>

cmd/tofu/signal_unix.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows
-// +build !windows
 
 package main
 

cmd/tofu/signal_windows.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build windows
-// +build windows
 
 package main
 

internal/command/cliconfig/config_locations_macos_test.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build darwin
-// +build darwin
 
 package cliconfig
 

internal/command/cliconfig/config_locations_unix_test.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows && !darwin
-// +build !windows,!darwin
 
 package cliconfig
 

internal/command/cliconfig/config_locations_windows_test.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build windows
-// +build windows
 
 package cliconfig
 

internal/command/cliconfig/config_unix.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows
-// +build !windows
 
 package cliconfig
 

internal/command/cliconfig/config_unix_test.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows
-// +build !windows
 
 package cliconfig
 

internal/command/cliconfig/config_windows.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build windows
-// +build windows
 
 package cliconfig
 

internal/command/testdata/login-oauth-server/main.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 // This file is a helper for those doing _manual_ testing of "tofu login"
 // and/or "tofu logout" and want to start up a test OAuth server in a

internal/communicator/ssh/communicator_test.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !race
-// +build !race
 
 package ssh
 

internal/flock/filesystem_lock_unix.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows
-// +build !windows
 
 package flock
 

internal/flock/filesystem_lock_windows.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build windows
-// +build windows
 
 package flock
 

internal/replacefile/replacefile_unix.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows
-// +build !windows
 
 package replacefile
 

internal/replacefile/replacefile_windows.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build windows
-// +build windows
 
 package replacefile
 

internal/terminal/impl_others.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build !windows
-// +build !windows
 
 package terminal
 

internal/terminal/impl_windows.go

@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //go:build windows
-// +build windows
 
 package terminal