internal/lsp: fix typo on license year

Change-Id: I5643ce049bad0dfb45405c06adc7c2eb46a394ac
Reviewed-on: https://go-review.googlesource.com/c/tools/+/177017
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/internal/lsp/source/hover.go b/internal/lsp/source/hover.go
index fb9a194..ede27af 100644
--- a/internal/lsp/source/hover.go
+++ b/internal/lsp/source/hover.go
@@ -1,4 +1,4 @@
-// Copyright 201p The Go Authors. All rights reserved.
+// Copyright 2019 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.