Code search 3.3 tracking issue

Created by: ijsnow

User story

@ijt, @ijsnow, @attfarhan : Could someone provide a paragraph on why these specific set of issues, the benefits and who this will help. This helps greatly with the writing of the blog post.

Examples at #2025 (closed) and #2848 (closed)

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• Track down issue that https://app.hubspot.com/contacts/2762526/company/887065580 is seeing where they're not seeing any results with indexed search enabled #3294 (closed)
• Auto-fix queries with invalid regexes #2125 (closed)
• Nested search @ijsnow @ijt (not going to be completed)
  • Delete !hier! feature flag/code path
  • Nested query performance tracking (not going to be completed)
    • Design document
    • Implementation #2879 (closed) (not going to be completed)
      • recent_searches table
      • report generating endpoint for nest querying enabled/disabled benchmark(not going to be completed)
• If searcher zip archives are corrupted, we should gracefully handle it #1759 (closed) (stretch) (not going to be completed)
• Search keyword to enable searching of large file sizes #1624 (closed)(not going to be completed)
• Saved search improvements @attfarhan https://github.com/sourcegraph/sourcegraph/issues/2824
• Search web app testability @attfarhan
  • Increase code coverage of web/src/search/results/ directory from 0% to >80%
  • Increase code coverage of web/src/search/saved-queries/ directory from 0% to >80% (stretch)
  • For each of shared/src/components/{CodeExcerpt.tsx, FileMatch.tsx, ResultContainer.tsx, FileMatchChildren.tsx}, increase code coverage from 0% to >80%
• Add syntax highlighting to code blocks in markdown files https://github.com/sourcegraph/sourcegraph/issues/2144~ (not going to be completed) @attfarhan
• Ability for admins to see top 100 recent searches (stretch) #3256 (closed) (not going to be completed)