chore(recent-media + intro): add proper headers and descriptions

src/assets/styles/base/index.css

@@ -363,7 +363,7 @@ article {
     border-bottom: var(--border-gray);
   }
 
-  &.intro p {
+  &.intro h2 {
     margin-top: 0;
   }
 

src/includes/home/recent-media.liquid

@@ -1,4 +1,9 @@
 <article>
+  <h2>
+    {% tablericon "activity" %}
+    Recent media
+  </h2>
+  <p>My top <a href="/music/this-week/artists/" class="music">artists</a>, <a href="/music/this-week/albums/" class="music">albums</a>, recently <a href="/books/years/{{ "now" | date: "%Y" }}/" class="books">read books</a>, watched <a href="/watching/recent/movies/" class="tv">movies</a> and <a href="/watching/recent/shows/" class="tv">shows</a>. A living snapshot, if you will.</p>
   {% render "media/grid.liquid",
     globals:globals,
     data:media.recentMusic,