fix: canonicalize shared URL paths

src/main.ts

@@ -129,6 +129,7 @@ function currentShareState(config = readConfig()): ShareState {
 
 function canonicalUrl(config = readConfig()): URL {
   const url = new URL(window.location.href);
+  if (url.pathname.endsWith("/index.html")) url.pathname = url.pathname.slice(0, -"index.html".length);
   url.search = encodeShareState(currentShareState(config));
   url.hash = "";
   return url;