Fix code blocks in `jobs.<job_id>.runs-on` document are not highlighted (#25846)

Co-authored-by: Siara <108543037+SiaraMist@users.noreply.github.com>

data/reusables/actions/jobs/section-choosing-the-runner-for-a-job.md

@@ -9,14 +9,14 @@ Use `jobs.<job_id>.runs-on` to define the type of machine to run the job on.
   - a single variable containing a string
   - an array of strings, variables containing strings, or a combination of both
 - If you specify an array of strings or variables, your workflow will execute on any runner that matches all of the specified `runs-on` values. For example, here the job will only run on a self-hosted runner that has the labels `linux`, `x64`, and `gpu`:
-  ```
+  ```yaml
   runs-on: [self-hosted, linux, x64, gpu]
   ```
   For more information, see "[Choosing self-hosted runners](#choosing-self-hosted-runners)."
 - You can mix strings and variables in an array. For example:
 
   {% raw %}
-  ```
+  ```yaml
   on:
     workflow_dispatch:
       inputs: