Add support for wp_login_form()

[kminh]

Resolves:

• https://wordpress.org/support/topic/how-to-use-this-with-wp-login-form?replies=2#post-8554433
• https://wordpress.org/support/topic/getting-bwp-recaptcha-to-work-with-bookly-plugin?replies=1#post-8586749