Fix code sample variable name (#6732)

api/advanced-topics/remote-extensions.md

@@ -232,7 +232,7 @@ import * as vscode from 'vscode';
 
 export function activate(context: vscode.ExtensionContext) {
     // ...
-    const apiKey = context.secrets.get('apiKey');
+    const myApiKey = context.secrets.get('apiKey');
     // ...
     context.secrets.delete('apiKey');
     // ...