Fix an undefined access when an edit is done before cpptools starts (#13206)

* Fix an undefined access.

Author: sean-mcmanus

Diff for: Extension/src/LanguageServer/client.ts

@@ -1842,7 +1842,8 @@ export class DefaultClient implements Client {
     public onDidChangeTextDocument(textDocumentChangeEvent: vscode.TextDocumentChangeEvent): void {
         if (util.isCpp(textDocumentChangeEvent.document)) {
             // If any file has changed, we need to abort the current rename operation
-            if (workspaceReferences.renamePending) {
+            if (workspaceReferences !== undefined // Occurs when a document changes before cpptools starts.
+                && workspaceReferences.renamePending) {
                 workspaceReferences.cancelCurrentReferenceRequest(refs.CancellationSender.User);
             }
 

Diff for: Extension/src/LanguageServer/extension.ts

@@ -298,7 +298,7 @@ async function onDidChangeSettings(event: vscode.ConfigurationChangeEvent): Prom
     }
 }
 
-async function onDidChangeTextDocument(event: vscode.TextDocumentChangeEvent): Promise<void> {
+function onDidChangeTextDocument(event: vscode.TextDocumentChangeEvent): void {
     const me: Client = clients.getClientFor(event.document.uri);
     me.onDidChangeTextDocument(event);
 }