refactor mux path routes

legend has it that if you refactor your code enough times, one day you
will finally be happy

admin/static/artists.js

@@ -18,7 +18,7 @@ document.addEventListener("readystatechange", () => {
         }).then(res => {
             res.text().then(text => {
                 if (res.ok) {
-                    location = "/admin/artists/" + id;
+                    location = "/admin/music/artists/" + id;
                 } else {
                     alert(text);
                     console.error(text);