Show a warning when using wrong executable

This commit updates the 'wdcli' command to show a warning when using the
wrong executable.

internal/fsx/type.go

@@ -1,17 +1,23 @@
+// Package fsx provides convenient abstractions to work with the filesystem.
 package fsx
 
-import "os"
+import (
+	"os"
+)
 
+// Exists checks if the given path exists
 func Exists(path string) bool {
 	_, err := os.Stat(path)
 	return err == nil
 }
 
+// IsDirectory checks if the provided path exists and is a directory
 func IsDirectory(path string) bool {
 	info, err := os.Stat(path)
 	return err == nil && info.Mode().IsDir()
 }
 
+// IsFile checks if the provided path exists and is a regular file
 func IsFile(path string) bool {
 	info, err := os.Stat(path)
 	return err == nil && info.Mode().IsRegular()