Add filters above forms in wp-login.php

[dimadin]

Sometimes I need more descriptive text to have above forms on wp-login.php (login, register, lost password).

This patch add filters above those forms.

Example usage:

function above_login_form_filter() {
	return '<p class="message">Tip: If you forgot your password, go to <a href="wp-login.php?action=lostpassword">Lost Password</a> page</p>';
}
add_filter('above_login_form','above_login_form_filter');

I can see this though I'm not a fan of adding several filters that all basically have the same purpose. Also, I'd rename it/the hooks to before_$action_form.