/// <summary>
/// Adds the given icon to the start of a navigation button.
/// </summary>
/// <example>
/// @n.Submit("Submit").WithIcon("arrow-right")
/// // Output:
/// <button type="submit"><span class="glyphicon glyphicon-arrow-right"></span> Submit</button>
/// </example>
/// <param name="attrs">The Html Attributes from a navigation button</param>
/// <param name="icon">The icon to use; see https://getbootstrap.com/docs/3.3/components/#glyphicons</param>
/// <returns>The Html Attribute object so other methods can be chained off of it</returns>
public static ButtonHtmlAttributes WithIcon(this ButtonHtmlAttributes attrs, string icon)
{
attrs.Attr(TwitterBootstrap3FormTemplate.IconAttrKey, icon);
return(attrs);
}