[regression] search help not shown anymore in https://forum.nim-lang.org/

[timotheecour]

IIRC https://forum.nim-lang.org/ used to show a question mark next to search bar that led to public/search-help.rst but not anymore; it's impossible for users to know of special search features described there

[jyapayne]

Ah, that is helpful to know about. I'll look into adding that back :)