add exnihil button

_layouts/shr4pnel.html

@@ -234,6 +234,13 @@ layout: compress
                             loading="lazy"
                     />
                 </a>
+                <a href="https://exnihl.neocities.org/" target="_blank" rel="noreferrer">
+                    <img
+                            src="/assets/buttons/exnihil.gif"
+                            alt="exnihil's button, thanks for adding mine, and sorry for not finding it sooner"
+                            loading="lazy"
+                    />
+                </a>
             </div>
             <h2 class="highlighted">webrings</h2>
             <div class="flex-wrap">