docs: adjust testing docs

Author: nartc

apps/astro-docs/src/content/docs/blog/v2.mdx

@@ -385,14 +385,14 @@ The testing API is currently in Developer Preview and may be subject to changes
 
 :::
 
-### Key Features
+#### Key Features
 
 1. **NgtTestBed**: A utility that extends Angular's TestBed, specifically tailored for Angular Three components.
 2. **Mocked Rendering**: Tests run without actual 3D rendering, focusing on scene graph state assertions.
 3. **Event Simulation**: Ability to simulate Three.js-specific events like `click`, `pointerover`, etc.
 4. **Animation Frame Control**: Methods to advance animation frames for testing time-based behaviors.
 
-### Basic Usage
+#### Basic Usage
 
 Here's a simple example of how you might use the testing utilities: