Simplify kubectl heredoc usage in cheatsheet

Remove the unnecessary cat command.

Author: juergenhoetzel

content/en/docs/reference/kubectl/cheatsheet.md

@@ -115,7 +115,7 @@ kubectl create cronjob hello --image=busybox:1.28   --schedule="*/1 * * * *" --
 kubectl explain pods                           # get the documentation for pod manifests
 
 # Create multiple YAML objects from stdin
-cat <<EOF | kubectl apply -f -
+kubectl apply -f - <<EOF
 apiVersion: v1
 kind: Pod
 metadata:
@@ -142,7 +142,7 @@ spec:
 EOF
 
 # Create a secret with several keys
-cat <<EOF | kubectl apply -f -
+kubectl apply -f - <<EOF
 apiVersion: v1
 kind: Secret
 metadata: