fix typo: if -> it

cmd/kubeadm/app/cmd/completion.go

@@ -73,7 +73,7 @@ var (
 		# Load the kubeadm completion code for bash into the current shell
 		source <(kubeadm completion bash)
 
-		# Write bash completion code to a file and source if from .bash_profile
+		# Write bash completion code to a file and source it from .bash_profile
 		kubeadm completion bash > ~/.kube/kubeadm_completion.bash.inc
 		printf "\n# Kubeadm shell completion\nsource '$HOME/.kube/kubeadm_completion.bash.inc'\n" >> $HOME/.bash_profile
 		source $HOME/.bash_profile