Fix typo in word 'occurred'

src/locales/en.json

@@ -581,7 +581,7 @@
       "err_network": "A network error occurred.",
       "err_decode": "Could not decode audio.",
       "err_unallowed": "Reproduction not allowed.",
-      "err_unknown": "An unexpected error has ocurred. Try again in a few minutes or report the item if the issue persists.",
+      "err_unknown": "An unexpected error has occurred. Try again in a few minutes or report the item if the issue persists.",
       "err_unsupported": "This audio format is not supported by your browser.",
       "loading": "Loading..."
     },