Add an example of our CommentStripper that doubles as a test

pkg/stripper/comments_example_test.go

@@ -0,0 +1,31 @@
+package stripper_test
+
+import (
+	"io"
+	"os"
+	"strings"
+
+	"github.com/docker-library/go-dockerlibrary/pkg/stripper"
+)
+
+func ExampleCommentStripper() {
+	r := strings.NewReader(`
+# opening comment
+a: b
+# comment!
+c: d # not a comment
+
+# another cheeky comment
+e: f
+`)
+
+	comStrip := stripper.NewCommentStripper(r)
+
+	io.Copy(os.Stdout, comStrip)
+
+	// Output:
+	// a: b
+	// c: d # not a comment
+	//
+	// e: f
+}