function createInput(key, title, placeholder) {
    return m("div.option", { class: key }, [
        m("label", [
            title,
            m("input[type=text]", {
                value: this.settings[key],
                placeholder: placeholder,
                onchange: (e) => {
                    this.settings[key] = e.target.value;
                    this.saveEnabled = true;
                },
            }),
        ]),
    ]);
}
Generates vnode for a input setting

@since 3.0.0

@param string key    Settings key
@param string title  Settings title
@param string placeholder  Settings placeholder
@return Vnode