docs: fix package.json field name

src/vs/vscode.d.ts

@@ -10054,7 +10054,7 @@ declare module 'vscode' {
 	 * 	return api;
 	 * }
 	 * ```
-	 * When depending on the API of another extension add an `extensionDependency`-entry
+	 * When depending on the API of another extension add an `extensionDependencies`-entry
 	 * to `package.json`, and use the [getExtension](#extensions.getExtension)-function
 	 * and the [exports](#Extension.exports)-property, like below:
 	 *