search: rename query to patternInfo

Created by: rvantonder

This is stacked on top of #7182.

The Zoekt code names the PatternInfo type query everywhere. Let's name it patternInfo for now--it doesn't have to stay this way, but it will make refactoring things easier later. The aim later is to refactor the PatternInfo type to separate things instead of bundling all of the Zoekt/Searcher/Regex/Structural/Commit/Diff/Repo parameters all in a mostly flat struct.

Semantics preserving, tests pass.

Created by: codecov[bot]

Codecov Report

Merging #7183 into rvt/pattern-info will not change coverage. The diff coverage is 93.33%.

@@                Coverage Diff                @@
##           rvt/pattern-info    #7183   +/-   ##
=================================================
  Coverage             39.19%   39.19%           
=================================================
  Files                  1230     1230           
  Lines                 64159    64159           
  Branches               6066     6066           
=================================================
  Hits                  25150    25150           
  Misses                36709    36709           
  Partials               2300     2300

Impacted Files	Coverage Δ
cmd/frontend/graphqlbackend/zoekt.go	73.39% <93.33%> (ø)