refactor: remove stray noResultStructure.html

This seems to have been moved in
c986fc5,
but without any context. I can't see it referenced anywhere and I also
see that it's actually in
https://github.com/lampepfl/dotty/blob/d332059144b10102ca4d1c433d294309b43f1e51/scaladoc-js/main/src/searchbar/SearchbarComponent.scala#L105-L113,
which makes me want to think this was never meant to be here. Testing
locally this also seems to work just fine without this.

Author: ckipp01