[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>

.markdownlint.yaml

@@ -0,0 +1,15 @@
+MD007:
+  indent: 4
+MD013: false
+MD024:
+  siblings_only: true
+MD031:
+  list_items: false
+MD029: false
+MD036: false
+MD033: false
+MD041: false
+MD046: false
+MD052: false
+MD053: false
+MD059: false