Fixing issues as per suggestions from @kevcunnane

src/Microsoft.SqlTools.ServiceLayer/Workspace/Contracts/FileChange.cs

@@ -0,0 +1,38 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.SqlTools.ServiceLayer.Workspace.Contracts
+{
+    /// <summary>
+    /// Contains details relating to a content change in an open file.
+    /// </summary>
+    public class FileChange
+    {
+        /// <summary>
+        /// The string which is to be inserted in the file.
+        /// </summary>
+        public string InsertString { get; set; }
+
+        /// <summary>
+        /// The 1-based line number where the change starts.
+        /// </summary>
+        public int Line { get; set; }
+
+        /// <summary>
+        /// The 1-based column offset where the change starts.
+        /// </summary>
+        public int Offset { get; set; }
+
+        /// <summary>
+        /// The 1-based line number where the change ends.
+        /// </summary>
+        public int EndLine { get; set; }
+
+        /// <summary>
+        /// The 1-based column offset where the change ends.
+        /// </summary>
+        public int EndOffset { get; set; }
+    }
+}