fix: add CSS to style footnotes correctly

As noted in pypa/readme_renderer#264

With these changes, the footnotes are styled in a more visually-pleasing
manner.

Signed-off-by: Mike Fiedler <miketheman@gmail.com>

warehouse/static/sass/blocks/_project-description.scss

@@ -263,6 +263,14 @@
     text-decoration: none;
   }
 
+  aside.footnote p {
+    display: inline;
+  }
+
+  aside.footnote {
+    padding-left: 2em;
+    text-indent: -2em;
+  }
 }