fix: navbar active link highlighting and scrolling
Fixes edge case caused due to responsive navbar height. More
specifically, a possible race condition between Scrollspy init and
updating its offset.
Fix #1199
-<body id="top" data-spy="scroll" data-target="{{ if or .IsHome (eq .Type "widget_page") }}#navbar-main{{else}}#TableOfContents{{end}}" {{ if not (.Scratch.Get "light") }}class="dark"{{end}}>
+<body id="top" data-spy="scroll" data-offset="70" data-target="{{ if or .IsHome (eq .Type "widget_page") }}#navbar-main{{else}}#TableOfContents{{end}}" {{ if not (.Scratch.Get "light") }}class="dark"{{end}}>
George Cushen