Improve fs package and doc in prep to officially go public

pkg/fs/confirmeddir.go

@@ -1,18 +1,5 @@
-/*
-Copyright 2018 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
 
 package fs
 
@@ -27,7 +14,7 @@ import (
 type ConfirmedDir string
 
 // NewTmpConfirmedDir returns a temporary dir, else error.
-// The directory is cleaned, no symlinks, etc. so its
+// The directory is cleaned, no symlinks, etc. so it's
 // returned as a ConfirmedDir.
 func NewTmpConfirmedDir() (ConfirmedDir, error) {
 	n, err := ioutil.TempDir("", "kustomize-")
@@ -36,13 +23,12 @@ func NewTmpConfirmedDir() (ConfirmedDir, error) {
 	}
 
 	// In MacOs `ioutil.TempDir` creates a directory
-	// with root in the `/var` folder, which is in turn a symlinked path
-	// to `/private/var`.
+	// with root in the `/var` folder, which is in turn
+	// a symlinked path to `/private/var`.
 	// Function `filepath.EvalSymlinks`is used to
 	// resolve the real absolute path.
 	deLinked, err := filepath.EvalSymlinks(n)
 	return ConfirmedDir(deLinked), err
-
 }
 
 // HasPrefix returns true if the directory argument