Add close operation to workspace documents API

Agent-Logs-Url: https://github.com/PowerShell/PowerShellEditorServices/sessions/6a4ffcb3-ffa5-431d-8a79-d5c87df48a9c

Co-authored-by: JustinGrote <15258962+JustinGrote@users.noreply.github.com>

Author: Copilot

src/PowerShellEditorServices/Extensions/EditorWorkspace.cs

@@ -30,6 +30,11 @@ internal EditorWorkspaceDocument(EditorWorkspace workspace, string path)
         /// Saves this document in the editor.
         /// </summary>
         public void Save() => _workspace.SaveFile(Path);
+
+        /// <summary>
+        /// Closes this document in the editor.
+        /// </summary>
+        public void Close() => _workspace.CloseFile(Path);
     }
 
     /// <summary>

test/PowerShellEditorServices.Test/Extensions/EditorWorkspaceTests.cs

@@ -32,7 +32,7 @@ public void DocumentsReturnsOpenWorkspaceDocuments()
         }
 
         [Fact]
-        public void DocumentOpenAndSaveUseWorkspaceOperations()
+        public void DocumentOpenSaveAndCloseUseWorkspaceOperations()
         {
             const string filePath = @"C:\test\file.ps1";
             TestEditorOperations editorOperations = new()
@@ -45,11 +45,13 @@ public void DocumentOpenAndSaveUseWorkspaceOperations()
 
             document.Open();
             document.Save();
+            document.Close();
 
             Assert.Collection(
                 editorOperations.Calls,
                 call => Assert.Equal("OpenFile:" + filePath, call),
-                call => Assert.Equal("SaveFile:" + filePath, call));
+                call => Assert.Equal("SaveFile:" + filePath, call),
+                call => Assert.Equal("CloseFile:" + filePath, call));
         }
 
         private sealed class TestEditorOperations : IEditorOperations
@@ -80,7 +82,11 @@ public Task OpenFileAsync(string filePath)
 
             public Task OpenFileAsync(string filePath, bool preview) => Task.CompletedTask;
 
-            public Task CloseFileAsync(string filePath) => Task.CompletedTask;
+            public Task CloseFileAsync(string filePath)
+            {
+                Calls.Add("CloseFile:" + filePath);
+                return Task.CompletedTask;
+            }
 
             public Task SaveFileAsync(string filePath)
             {