No mobile device touch support for abstract "i" button

[rmseifried]

Description

The default code exported from the qgis2web plugin does not allow for touch events on the abstract "i" button - on a desktop, clicking "i" expands the abstract, but on a mobile device, touching "i" does nothing. I suspect this is because there is JS code for the zoom controls, geocoder, and layers buttons that allows for touch actions, but the abstract collapse is dealt with only in the index.html file:

        abstract.onAdd = function (map) {
            this._div = L.DomUtil.create('div',
            'leaflet-control abstract');
            this._div.id = 'abstract'
            this._div.setAttribute("onmouseenter", "abstract.show()");
            this._div.setAttribute("onmouseleave", "abstract.hide()");
            this.hide();
            return this._div;
            };

            abstract.hide = function () {
              this._div.classList.remove("abstractUncollapsed");
              this._div.classList.add("abstract");
              this._div.innerHTML = 'i'
            }
            abstract.show = function () {
                this._div.classList.remove("abstract");
                this._div.classList.add("abstractUncollapsed");
                this._div.innerHTML = "Map of Patrick (Paddy) and Joan Leigh Fermors' first trip through the Deep Mani in the southern Peloponnese, Greece, in July 1951. For more information about the data and methodology behind this map, see the article <em>Mapping the Leigh Fermors’ Journey through the Deep Mani in 1951</em> by R.M. Seifried, C.A.M. Gardner, and M. Tatum (link will be added when it is published). Data for the web map are available on <a href='https://github.com/rmseifried/leigh-fermors'>GitHub</a>.";
        };

Related issues

qgis2web/qgis2web#863
qgis2web/qgis2web#904