add license headers

Author: Mpdreamz

tests/authoring/Framework/MarkdownResultsAssertions.fs

@@ -1,3 +1,7 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
 namespace authoring
 
 open System.Diagnostics

tests/authoring/Framework/TestValues.fs

@@ -6,8 +6,6 @@ namespace authoring
 
 open System
 open System.IO.Abstractions
-open System.Threading
-open System.Threading.Tasks
 open Elastic.Markdown
 open Elastic.Markdown.Diagnostics
 open Elastic.Markdown.IO