Bring back WriteWithPrompt() (#1781)

We were running into a situation where we'd print the prompt on the same
line that we had previously printed it. This was especially noticable
when stepping through the debugger. So we add the `WriteWithPrompt`
work-around back in.

Author: SeeminglyScience

src/PowerShellEditorServices/Services/PowerShell/Execution/SynchronousPowerShellTask.cs

@@ -62,7 +62,7 @@ public override IReadOnlyList<TResult> Run(CancellationToken cancellationToken)
 
                 if (PowerShellExecutionOptions.WriteInputToHost)
                 {
-                    _psesHost.UI.WriteLine(_psCommand.GetInvocationText());
+                    _psesHost.WriteWithPrompt(_psCommand, cancellationToken);
                 }
 
                 return _pwsh.Runspace.Debugger.InBreakpoint

src/PowerShellEditorServices/Services/PowerShell/Host/PsesInternalHost.cs

@@ -770,7 +770,7 @@ private void DoOneRepl(CancellationToken cancellationToken)
                 // one, but we do not want to print one if the ReadLine task was canceled.
                 if (string.IsNullOrEmpty(userInput))
                 {
-                    if (LastKeyWasCtrlC())
+                    if (cancellationToken.IsCancellationRequested || LastKeyWasCtrlC())
                     {
                         UI.WriteLine();
                     }
@@ -836,6 +836,19 @@ private string GetPrompt(CancellationToken cancellationToken)
             return prompt;
         }
 
+        /// <summary>
+        /// This is used to write the invocation text of a command with the user's prompt so that,
+        /// for example, F8 (evaluate selection) appears as if the user typed it. Used when
+        /// 'WriteInputToHost' is true.
+        /// </summary>
+        /// <param name="command">The PSCommand we'll print after the prompt.</param>
+        /// <param name="cancellationToken"></param>
+        public void WriteWithPrompt(PSCommand command, CancellationToken cancellationToken)
+        {
+            UI.Write(GetPrompt(cancellationToken));
+            UI.WriteLine(command.GetInvocationText());
+        }
+
         private string InvokeReadLine(CancellationToken cancellationToken)
         {
             try