wp_editor() doesn't support attributes besides id and class

[Shelob9]

I'm replacing a generic textarea with a WYSIWIG field. My textarea has an aria-describedby attribute, but wp_editor() -- really _WP_Editors::editor() -- can't set any HTML attributes besides ID and class on the WYSIWIG.

Would be better if I could do something like this:

	wp_editor( 'hi-roy', 'Some text', array(
		'attrs' => array(
			'aria-describedby' => 'description'
		)
	));
	echo '<p id="description">Some description</p>';