all: minor tweaks

Fix a typo in legacy_enum.go.
Rename package in ancient legacy proto so that it doesn't confuse
tooling that assume that the package and directory names match.

Change-Id: I0b896045e74b0a7f998d3e5693b853eb3aa3839c
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/214182
Reviewed-by: Joe Tsai <joetsai@google.com>
diff --git a/internal/impl/legacy_enum.go b/internal/impl/legacy_enum.go
index d17591f..f7d7ffb 100644
--- a/internal/impl/legacy_enum.go
+++ b/internal/impl/legacy_enum.go
@@ -1,6 +1,6 @@
 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
-// license that can be found in the LICEqNSE file.
+// license that can be found in the LICENSE file.
 
 package impl