docs: update migration filename
docs: update migration filename

Use make:migration's output filename and classname

bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,bcit-ci/CodeIgniter4