[doc] Fix the code-block directives

4 jobs for vuln-doc in 14 minutes and 26 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #231776
docker
build_linux_37

00:05:57

84.0%
passed #231777
docker
build_linux_38

00:05:56

84.0%
passed #231774
intel macos
build_macos_intel_37

00:14:26

84.0%
passed #231775
intel macos
build_macos_intel_38

00:14:16

84.0%