Fix erroneous cancellation tokens

These needed to be explicitly `None` to indicate that they should not be
cancelled (for various reasons).

Author: andyleejordan

src/PowerShellEditorServices/Services/DebugAdapter/Handlers/DisconnectHandler.cs

@@ -74,8 +74,8 @@ public async Task<DisconnectResponse> Handle(DisconnectArguments request, Cancel
             _logger.LogInformation("Debug adapter is shutting down...");
 
 #pragma warning disable CS4014
-            // Trigger the clean up of the debugger. No need to wait for it.
-            Task.Run(_psesDebugServer.OnSessionEnded, cancellationToken);
+            // Trigger the clean up of the debugger. No need to wait for it nor cancel it.
+            Task.Run(_psesDebugServer.OnSessionEnded, CancellationToken.None);
 #pragma warning restore CS4014
 
             return new DisconnectResponse();

src/PowerShellEditorServices/Services/PowerShellContext/Session/PSReadLinePromptContext.cs

@@ -144,7 +144,9 @@ public async Task<string> InvokeReadLineAsync(bool isCommandLine, CancellationTo
                 readLineCommand,
                 errorMessages: null,
                 s_psrlExecutionOptions,
-                cancellationToken).ConfigureAwait(false);
+                // NOTE: This command should always be allowed to complete, as the command itself
+                // has a linked cancellation token such that PSReadLine will be correctly cancelled.
+                CancellationToken.None).ConfigureAwait(false);
 
             string line = readLineResults.FirstOrDefault();
 

src/PowerShellEditorServices/Services/Symbols/Vistors/AstOperations.cs

@@ -62,7 +62,7 @@ public static async Task<CommandCompletion> GetCompletionsAsync(
             ILogger logger,
             CancellationToken cancellationToken)
         {
-            if (!s_completionHandle.Wait(0, cancellationToken))
+            if (!s_completionHandle.Wait(0, CancellationToken.None))
             {
                 return null;
             }