Exception in IE11 when applying formatters

[jcubic]

Issue summary

There is exception in IE11 while trying to apply formatters

Steps to reproduce

1. Open demo in IE11
2. Press enter few times

The issue came from this function:

    function count_selfclosing_formatting(e) {
        var n = 0;
        if ($.terminal.have_formatting(e)) {
            var r = new RegExp(format_parts_re,"i");
            $.terminal.format_split(e).forEach(function(e) {
                if ($.terminal.is_formatting(e)) {
                    var t = e.match(r);
                    if (t && t[1].match(/@/) && t[6] === "") {
                        n++
                    }
                }
            })
        }
        return n
    }

format_parts_re is regex that it's used to create new regex without g flag, the code should use format_parts_re.source that is supported in IE11.

Browser and OS

Windows 10, IE11