Fix minor whitespace issue on item page "Occupies" zone list

Ahh right, when you indent stuff underneath a tag in HAML, it does the
same indented form in the output HTML, which adds whitespace that
creates a problem for how we're doing this list.

Before this change, the "Engulfed in Flames Effect" item showed below
the preview: `Occupies: Background Item , Lower Foreground Item`, with
an extra space before the comma.

After this change, it now shows
`Occupies: Background Item, Lower Foreground Item`, as intended.

app/views/items/show.html.haml

@@ -67,7 +67,7 @@
         - if @appearances_by_occupied_zone.present?
           %ul
             - @appearances_by_occupied_zone.each do |zone, appearances_in_zone|
-              %li
+              %li<
                 = zone.label
                 - if item_zone_partial_fit? appearances_in_zone, @all_appearances
                   %span.zone-species-info{