chore: add a test typescript file

tests/syntax-tests/highlighted/Markdown/typescript.md

@@ -0,0 +1,57 @@
+# Typescript test
+
+```typescript
+enum Status {
+    Pending,
+    InProgress,
+    Completed,
+}
+
+interface Task {
+    id: number;
+    title: string;
+    status: Status;
+    assignee?: string;
+}
+
+class TaskManager<T extends Task> {
+    private tasks: T[] = [];
+
+    addTask(task: T): void {
+        this.tasks.push(task);
+    }
+
+    getTasksByStatus(status: Status): T[] {
+        return this.tasks.filter(task => task.status === status);
+    }
+
+    async fetchTasks(): Promise<T[]> {
+        // Simulate async fetch
+        return new Promise(resolve => setTimeout(() => resolve(this.tasks), 500));
+    }
+}
+
+// Type guard
+function isTask(obj: any): obj is Task {
+    return typeof obj.id === 'number' && typeof obj.title === 'string';
+}
+
+// Usage
+const manager = new TaskManager<Task>();
+manager.addTask({ id: 1, title: "Write docs", status: Status.Pending });
+manager.addTask({ id: 2, title: "Review PR", status: Status.InProgress, assignee: "Alice" });
+
+(async () => {
+    const allTasks = await manager.fetchTasks();
+    allTasks.forEach(task => {
+        if (isTask(task)) {
+            console.log(`Task #${task.id}: ${task.title} [${Status[task.status]}]`);
+        }
+    });
+})();
+
+// Type assertion
+const unknownValue: unknown = { id: 3, title: "Test", status: Status.Completed };
+const assertedTask = unknownValue as Task;
+console.log(assertedTask.title);
+```