Simplify search qualifiers

[ns-wkso]

Can we make the qualifiers simpler? Like we support language: and repo: and path: et al, but how about l: r: and p: also? Sourcegraph and other code search solutions do this.

[colinwm]

We do have an undocumented lang: shorthand for language:. But I think four characters should be OK for a qualifier, right? By making them much shorter the query language becomes more overloaded and cryptic, so I'm hesitant to do it.

But if lots of people agree, maybe we can reconsider.

[ns-wkso]

I was told engineers are lazy, so the shorter the better but I think lang is good. Are there other undocumented ones? Would they be documented at some point? I guess now we have to do path: to find specific file name. Is there a file: or f: or something more intuitive when searching for file name?