search docs: update search query language docs to reflect `repo:has.(...)` syntax
Created by: tbliu98
Updating search query language docs page to reflect new repo:has.(...)
predicate syntax.
Removed the -repohasfile
example as repohasfile
is deprecated and we should be able to provide an example of a negated repo:has.file(...)
query once https://github.com/sourcegraph/sourcegraph/pull/40283 is merged.
Test plan
Manually verified changes and working links locally