Accessibility: Improve the password form buttons accessibility.

- makes the "Cancel" button always visible: this allows to generate a new password also on small screens
- moves focus back to the Generate Password button when closing the form
- changes the password reset show/hide button from a clickable `<span>` element to a real `<button>` element
- improves the CSS

Props janak007, afercia.
Fixes #42853.

Built from https://develop.svn.wordpress.org/trunk@44895


git-svn-id: http://core.svn.wordpress.org/trunk@44726 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/user-edit.php

@@ -618,10 +618,11 @@ endif; //!IS_PROFILE_PAGE
 				<input type="password" name="pass1" id="pass1" class="regular-text" value="" autocomplete="off" data-pw="<?php echo esc_attr( wp_generate_password( 24 ) ); ?>" aria-describedby="pass-strength-result" />
 			</span>
 			<button type="button" class="button wp-hide-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
-				<span class="dashicons dashicons-hidden"></span>
+				<span class="dashicons dashicons-hidden" aria-hidden="true"></span>
 				<span class="text"><?php _e( 'Hide' ); ?></span>
 			</button>
 			<button type="button" class="button wp-cancel-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Cancel password change' ); ?>">
+				<span class="dashicons dashicons-no" aria-hidden="true"></span>
 				<span class="text"><?php _e( 'Cancel' ); ?></span>
 			</button>
 			<div style="display:none" id="pass-strength-result" aria-live="polite"></div>