fix: work around askama parsing bugs

It doesn't seem to like nesting a block inside a match, so let's use the
older approach of including the block from a separate file for now
instead.

server/src/scrobble.rs

···
 }
 
 #[derive(Template, Debug, Clone)]
-#[template(path = "index.html", block = "scrobbles")]
+#[template(path = "scrobble.html")]
 pub struct ScrobblesTemplate {
     pub intro: &'static str,
     pub now_playing: String,

server/templates/index.html

···
     </div>
     <div class="scrobble-bar" hx-get="/scrobbles" hx-trigger="every 30s">
       {% match scrobble %} {% when Some with (ScrobblesTemplate {intro, now_playing, image, srcset}) %}
-      {% block scrobbles %}
-      <div class="bar-container">
-        {% match image %} {% when Some with (image) %}
-        <img
-          class="bar-cover"
-          src="{{ image }}"
-          alt="Cover art"
-          {% match srcset %} {% when Some with (srcset) %}
-            srcset="{{ srcset }}"
-          {% else %}
-          {% endmatch %}
-        />
-        {% else %}
-        {% endmatch %}
-        <p class="bar-text-intro">{{ intro }}</p>
-        <p class="bar-text-music">{{ now_playing }}</p>
-      </div>
-      {% endblock scrobbles %}
+      {% include "scrobble.html" %}
       {% else %}
       {% endmatch %}
     </div>

server/templates/scrobble.html

···
+<div class="bar-container">
+  {% match image %} {% when Some with (image) %}
+  <img
+  class="bar-cover"
+  src="{{ image }}"
+  alt="Cover art"
+  {% match srcset %} {% when Some with (srcset) %}
+  srcset="{{ srcset }}"
+  {% else %}
+  {% endmatch %}
+  />
+  {% else %}
+  {% endmatch %}
+  <p class="bar-text-intro">{{ intro }}</p>
+  <p class="bar-text-music">{{ now_playing }}</p>
+</div>