patch: Mark 404 as a successful response

This is discussed in detail several places, e.g:
hotwired#188 (comment)

go.mod

@@ -0,0 +1,3 @@
+module github.com/bep/turbo
+
+go 1.19

src/core/drive/visit.ts

@@ -420,5 +420,10 @@ export class Visit implements FetchRequestDelegate {
 }
 
 function isSuccessful(statusCode: number) {
+  if (statusCode == 404) {
+    // Temporary patch (bep).
+    // In most cases, a 404 response is, from a rendering perspective, a successful response.
+    return true
+  }
   return statusCode >= 200 && statusCode < 300
 }