Minor markup tweaks in render_frame_capture.md (#51480)

diff --git a/impeller/docs/renderdoc_frame_capture.md b/impeller/docs/renderdoc_frame_capture.md
index 247ec7e..0257b9d 100644
--- a/impeller/docs/renderdoc_frame_capture.md
+++ b/impeller/docs/renderdoc_frame_capture.md
@@ -2,26 +2,31 @@
 
 [RenderDoc](https://renderdoc.org/) is a graphics debugger that can be used to capture frames. With Impeller starting to support OpenGL ES and Vulkan backends, RenderDoc can provide insights into the application's frames.
 
-1. First step is to set up RenderDoc. Follow the instructions [here](https://renderdoc.org/docs/getting_started/quick_start.html). For the purposes of this guide it is assumed that you are able to get RenderDoc running.
-2. The next step would be to run the application you wish the capture the frames of. Typically these would be one of the playground tests. To build these, do:
+1. First step is to set up RenderDoc. Follow the [quickstart instructions](https://renderdoc.org/docs/getting_started/quick_start.html).
+   For the purposes of this guide it is assumed that you are able to get RenderDoc running.
+3. The next step would be to run the application you wish the capture the frames of.
+   Typically these would be one of the [playground tests](https://github.com/flutter/engine/tree/main/impeller/playground).
+   To build these, do:
 
-```bash
-# In your $ENGINE_SRC folder, do:
+   ```bash
+   # In your $ENGINE_SRC folder, do:
 
-./flutter/tools/gn --unopt
-ninja -C out/host_debug_unopt/
-```
+   ./flutter/tools/gn --unopt
+   ninja -C out/host_debug_unopt/
+   ```
+
+   Building a "debug_unopt" build ensures that you have tracing enabled. Without this, RenderDoc will not have much to show.
 
 3. Start RenderDoc, and click the "Launch Application" button.
 
-![Launch App](assets/renderdoc_frame_capture/launch-app.png)
+   ![Launch App](assets/renderdoc_frame_capture/launch-app.png)
 
 4. Fill out the following parameters, and click launch:
 
-- executable: `$ENGINE_SRC/out/host_debug_impeller_vulkan/impeller_unittests` (expand `ENGINE_SRC`).
-- args: `--gtest_filter="*CanDrawRect/Vulkan*" --enable_playground`
-- working dir: `$ENGINE_SRC` (expand `ENGINE_SRC`)
+   - executable: `$ENGINE_SRC/out/host_debug_impeller_vulkan/impeller_unittests` (expand `ENGINE_SRC`).
+   - args: `--gtest_filter="*CanDrawRect/Vulkan*" --enable_playground`
+   - working dir: `$ENGINE_SRC` (expand `ENGINE_SRC`)
 
 5. For the frame you wish to capture, press `F12`, you will now be able to see the frame capture and inspect the state.
 
-![Renderdoc Capture](assets/renderdoc_frame_capture/render-doc-capture.png)
+   ![Renderdoc Capture](assets/renderdoc_frame_capture/render-doc-capture.png)