[Docs] Switch to better markdown linting pre-commit hook (#21851)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

docs/contributing/ci/failures.md

@@ -20,19 +20,19 @@ the failure?
 
 - **Use this title format:**
 
-    ```
+    ```text
     [CI Failure]: failing-test-job - regex/matching/failing:test
     ```
 
 - **For the environment field:**
 
-    ```
- Still failing on main as of commit abcdef123
+    ```text
+    Still failing on main as of commit abcdef123
     ```
 
 - **In the description, include failing tests:**
 
-    ```
+    ```text
     FAILED failing/test.py:failing_test1 - Failure description
     FAILED failing/test.py:failing_test2 - Failure description
     https://github.com/orgs/vllm-project/projects/20

docs/contributing/ci/update_pytorch_version.md

@@ -106,6 +106,7 @@ releases (which would take too much time), they can be built from
 source to unblock the update process.
 
 ### FlashInfer
+
 Here is how to build and install it from source with `torch2.7.0+cu128` in vLLM [Dockerfile](https://github.com/vllm-project/vllm/blob/27bebcd89792d5c4b08af7a65095759526f2f9e1/docker/Dockerfile#L259-L271):
 
 ```bash
@@ -121,6 +122,7 @@ public location for immediate installation, such as [this FlashInfer wheel link]
 team if you want to get the package published there.
 
 ### xFormers
+
 Similar to FlashInfer, here is how to build and install xFormers from source:
 
 ```bash
@@ -138,7 +140,7 @@ uv pip install --system \
 
 ### causal-conv1d
 
-```
+```bash
 uv pip install 'git+https://github.com/Dao-AILab/causal-conv1d@v1.5.0.post8'
 ```