More options

[zkelo]

This pull request includes:

• Bug fix
• New feature
• Translation

The following changes were made:

• Added new option searchDecorator;
• Added documentation for new option.

This PR helps to solve my issue #6262 by adding special option for specifying search decorator. Using this I can define custom search decorator and easy pass it to widget.

This is how I did it with new option:

// Decorator definition
$.fn.select2.amd.define('CustomSearch', [
    'select2/selection/search',
    'select2/utils'
], function (Search, Utils) {
    function CustomSearch (decorated, $element, options) {
        decorated.call(this, $element, options);
    }

    Utils.Extend(CustomSearch, Search);

    CustomSearch.prototype.searchRemoveChoice = function (decorated, item) {
        this.trigger('unselect', {
          data: item
        });

        this.$search.val(item.text.substr(0, item.text.indexOf('<') - 1));
        this.handleSearch();
    };

    return CustomSearch;
});

// Init select2
$('#books').select2({
    width: 500,
    multiple: true,
    data: [
        {
            id: 1,
            text: 'First book <span style="display: none;">one 1</span>'
        },
        {
            id: 2,
            text: 'Second book <span style="display: none;">two 2</span>'
        },
        {
            id: 3,
            text: 'Third book <span style="display: none;">three 3</span>'
        }
    ],
    escapeMarkup(data) {
        return data;
    },
    searchDecorator: $.fn.select2.amd.require('CustomSearch')
});

I think it will be useful not only for me so I made this PR. Also I can add more similar options and documentation for them if this will be useful.