Added aria labels to palette toggles

src/partials/header.html

@@ -75,6 +75,11 @@
             data-md-color-scheme="{{ option.scheme }}"
             data-md-color-primary="{{ primary }}"
             data-md-color-accent="{{ accent }}"
+            {% if option.toggle %}
+              aria-label="{{ option.toggle.name }}"
+            {% else  %}
+              aria-hidden="true"
+            {% endif %}
             type="radio"
             name="__palette"
             id="__palette_{{ loop.index }}"