plugins: Fix alias-completion by using helper util

By using _bash-it-array-contains-element, we can safetly iterate over
elements in the $completions array

plugins/available/alias-completion.plugin.bash

@@ -52,7 +52,7 @@ function alias_completion {
 		read -a alias_arg_words <<< "$alias_args"
 
 		# skip alias if there is no completion function triggered by the aliased command
-		if [[ ! " ${completions[*]} " =~ $alias_cmd ]]; then
+		if ! _bash-it-array-contains-element "$alias_cmd" "${completions[@]}"; then
 			if [[ -n "$completion_loader" ]]; then
 				# force loading of completions for the aliased command
 				eval "$completion_loader $alias_cmd"