Fix syntax errors (#27735)

* Fix syntax errors

- fix wrong placed line breaks
- fix command mode start and end

* remove word 'simple'

content/en/docs/reference/access-authn-authz/authentication.md

@@ -205,12 +205,10 @@ spec:
 ```
 
 Service account bearer tokens are perfectly valid to use outside the cluster and
-
 can be used to create identities for long standing jobs that wish to talk to the
-Kubernetes API. To manually create a service account, simply use the `kubectl`
-
-create serviceaccount (NAME)` command. This creates a service account in the
-current namespace and an associated secret.
+Kubernetes API. To manually create a service account, use the `kubectl create
+serviceaccount (NAME)` command. This creates a service account in the current
+namespace and an associated secret.
 
 ```bash
 kubectl create serviceaccount jenkins