jQuery( document ).ready( function ( $ ) {
    $( '#wpTextbox1' ).wikiEditor( 'addToToolbar', {
        section: 'advanced',
        group: 'format',
        tools: {
            buttonId: {
                label: 'Comment visible only for editors',
                type: 'button',
                icon: '//upload.wikimedia.org/wikipedia/commons/a/a0/Button_keep.png',
                action: {
                    type: 'encapsulate',
                    options: {
                        pre: '',
                        peri: '{{WP:NS/Vyřešeno}}',
                        post: ''
                    }
                }
            }
        }
    } );
} );