LICENSE: update per Google Legal

Very minor tweaks:
 - Remove (c) pseudosymbol.
 - Remove "All Rights Reserved."
 - Change "Google Inc." (no longer exists) to "Google LLC".

[git-generate]
echo '
,s/\(c\) //
,s/ All rights reserved.//
,s/Google Inc./Google LLC/
w
q
' | sam -d LICENSE

Change-Id: I9d9b10b2aa09bc97a3f8a072908181e5930f86aa
Reviewed-on: https://go-review.googlesource.com/c/xerrors/+/598591
Commit-Queue: Russ Cox <rsc@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Bypass: Russ Cox <rsc@golang.org>

LICENSE

diff --git a/LICENSE b/LICENSE
index e4a47e1..c3c8b7d 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2019 The Go Authors. All rights reserved.
+Copyright 2019 The Go Authors.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
@@ -10,7 +10,7 @@
 copyright notice, this list of conditions and the following disclaimer
 in the documentation and/or other materials provided with the
 distribution.
-   * Neither the name of Google Inc. nor the names of its
+   * Neither the name of Google LLC nor the names of its
 contributors may be used to endorse or promote products derived from
 this software without specific prior written permission.