[Lint]Style: reformat markdown files via markdownlint (#5884)

### What this PR does / why we need it?
reformat markdown files via markdownlint

- vLLM version: v0.13.0
- vLLM main:
bde38c11df

---------

Signed-off-by: root <root@LAPTOP-VQKDDVMG.localdomain>
Signed-off-by: MrZ20 <2609716663@qq.com>
Co-authored-by: root <root@LAPTOP-VQKDDVMG.localdomain>

docs/source/user_guide/configuration/additional_config.md

@@ -87,7 +87,7 @@ The details of each configuration option are as follows:
 
 An example of additional configuration is as follows:
 
-```
+```python
 {
     "weight_prefetch_config": {
         "enabled": True,