Added missing WillSaveWaitUntilTextDocumentParams model

Author: david-driscoll

src/Protocol/Document/Client/WillSaveWaitUntilTextDocumentExtensions.cs

@@ -9,7 +9,7 @@ namespace OmniSharp.Extensions.LanguageServer.Protocol.Client
 {
     public static class WillSaveWaitUntilTextDocumentExtensions
     {
-        public static Task WillSaveWaitUntilTextDocument(this ILanguageClientDocument mediator, WillSaveTextDocumentParams @params)
+        public static Task WillSaveWaitUntilTextDocument(this ILanguageClientDocument mediator, WillSaveWaitUntilTextDocumentParams @params)
         {
             return mediator.SendRequest(DocumentNames.WillSaveWaitUntil, @params);
         }

src/Protocol/Document/Server/IWillSaveWaitUntilTextDocumentHandler.cs

@@ -8,5 +8,5 @@ namespace OmniSharp.Extensions.LanguageServer.Protocol.Server
 {
     using static DocumentNames;
     [Serial, Method(WillSaveWaitUntil)]
-    public interface IWillSaveWaitUntilTextDocumentHandler : IJsonRpcRequestHandler<WillSaveTextDocumentParams>, IRegistration<TextDocumentRegistrationOptions>, ICapability<SynchronizationCapability> { }
+    public interface IWillSaveWaitUntilTextDocumentHandler : IJsonRpcRequestHandler<WillSaveWaitUntilTextDocumentParams, TextEditContainer>, IRegistration<TextDocumentRegistrationOptions>, ICapability<SynchronizationCapability> { }
 }

src/Protocol/Models/WillSaveWaitUntilTextDocumentParams.cs

@@ -0,0 +1,20 @@
+using MediatR;
+
+namespace OmniSharp.Extensions.LanguageServer.Protocol.Models
+{
+    /// <summary>
+    ///  The parameters send in a will save text document notification.
+    /// </summary>
+    public class WillSaveWaitUntilTextDocumentParams : IRequest<TextEditContainer>
+    {
+        /// <summary>
+        ///  The document that will be saved.
+        /// </summary>
+        public TextDocumentIdentifier TextDocument { get; set; }
+
+        /// <summary>
+        ///  The 'TextDocumentSaveReason'.
+        /// </summary>
+        public TextDocumentSaveReason Reason { get; set; }
+    }
+}