Remove unused CSS in legislation

This code using the legislation-categories HTML class was removed in
commits d679c1eb7 and ff66909cd. We've noticed is while dealing with the
`.menu.simple` selectors in the previous commit.

app/assets/stylesheets/legislation.scss

@@ -1,43 +1,3 @@
-// Table of Contents
-//
-// 01. Sidebar menu
-// 02. Legislation cards
-//
-
-// 01. Sidebar menu
-// -----------------
-.legislation-categories {
-
-  .menu.simple {
-    border-bottom: 0;
-    list-style: none;
-    padding-left: 0;
-    margin-left: 0;
-    margin-top: 0;
-
-    @include breakpoint(medium) {
-      margin: 1.5rem 0;
-    }
-
-    li {
-      display: block;
-      cursor: pointer;
-      margin-bottom: 1rem;
-
-      @include breakpoint(medium) {
-        margin-bottom: 2rem;
-        max-width: 80%;
-      }
-
-      &.is-active {
-        font-weight: 700;
-      }
-    }
-  }
-}
-
-// 02. Legislation cards
-// -----------------
 .legislation {
   margin: 0 0 $line-height;
   border: 1px solid;