Search should not be case-sensitive

[mortenpi]

In Documenter's own docs, searching for editurl doesn't yield any results:

But EditURL does:

We probably want to prioritize case-matches if we can, but I think we should not exclude results just because the case does not match.

FWIW, this seems to be a regression relative to the old search:

cc @Hetarth02

[Hetarth02]

Yup, I agree this should not be the case. I will try if I can fix this quickly.