Unicode characters incorrectly filled into the search bar on 404 pages

[CelDaemon]

When following a link that is no longer valid, a 404 page appears containing a search bar.
This search bar has relevant keywords from the URL pre-filled, however this behaviour is handled incorrectly when the URL contains characters that are represented with URI escape sequences.

In these cases, the keywords are directly filled into the search bar without first being decoded from the escape sequences.

[CelDaemon]

It seems to be an issue in the hugo theme, a piece of javascript that skips the decoding of special characters:

https://github.com/CaiJimmy/hugo-theme-stack/blob/839fbd0ecb5bba381f721f31f5195fb6517fc260/layouts/404.html#L35

[CelDaemon]

I have created an issue report on their side, as well as a simple fix.