docs: add why HTTP-verb-based routes are safer
docs: add why HTTP-verb-based routes are safer

The security related note should be `warning`.

lonnieezell/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,lonnieezell/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,lonnieezell/CodeIgniter4,samsonasik/CodeIgniter4,lonnieezell/CodeIgniter4,bcit-ci/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,samsonasik/CodeIgniter4,lonnieezell/CodeIgniter4,lonnieezell/CodeIgniter4,samsonasik/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4