Javascript: Add support for deep toc levels (#1089)

In ca015a5 support was added for tox levels up to 10.
This only fixed the css side, this commit makes a similar fix for the js side.

Fixes #893

src/theme.js

@@ -146,13 +146,10 @@ function ThemeNav () {
             if (link.length > 0) {
                 $('.wy-menu-vertical .current').removeClass('current');
                 link.addClass('current');
-                link.closest('li.toctree-l1').addClass('current');
                 link.closest('li.toctree-l1').parent().addClass('current');
-                link.closest('li.toctree-l1').addClass('current');
-                link.closest('li.toctree-l2').addClass('current');
-                link.closest('li.toctree-l3').addClass('current');
-                link.closest('li.toctree-l4').addClass('current');
-                link.closest('li.toctree-l5').addClass('current');
+                for (let i = 1; i <= 10; i++) {
+                    link.closest('li.toctree-l' + i).addClass('current');
+                }
                 link[0].scrollIntoView();
             }
         }