omit deprecated in loogle

Stream: general

[Kenny Lau]

Can we omit deprecated declarations in loogle? (e.g. first result in https://loogle.lean-lang.org/?q=ZMod%2C+Nat.ModEq)

[Kim Morrison]

I'm sure a PR would be welcome!

[Ruben Van de Velde]

I'm not sure about omitting, but flagging them somehow seems useful

[Joachim Breitner]

This is issue https://github.com/nomeata/loogle/issues/34