Remove the single diff strategy and make multi-diff the default

[mrubens]

Multi-diff is working well so this makes it the default and removes single diff. We also remove the diff strategy dropdown and just have the experimental checkbox for unified diff, though at this point I think we should get rid of unified diff soon assuming no negative feedback from this change.

---

Important

This pull request removes the single diff strategy, makes multi-diff the default, and updates related tests, code, and UI components.

• Behavior:
  • Removes single diff strategy and makes multi-diff the default in DiffStrategy.ts.
  • Removes diff strategy dropdown, retains experimental checkbox for unified diff.
• Tests:
  • Deletes search-replace.test.ts as it is no longer relevant.
• Code Cleanup:
  • Deletes search-replace.ts as the single diff strategy is removed.
  • Updates references from SearchReplaceDiffStrategy to MultiSearchReplaceDiffStrategy in system.test.ts and ExtensionStateContext.test.tsx.
• Experiments:
  • Removes multi_search_and_replace experiment ID from experiments.ts and related files.
• UI:
  • Removes diff strategy selection UI in AdvancedSettings.tsx.

^{This description was created by for 1fadf15. It will automatically update as commits are pushed.}

[changeset-bot]

⚠️ No Changeset found

Latest commit: 1fadf15

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[mrubens]

This was a bit of a mixup - SEARCH_AND_REPLACE here refers to the tool, not the diff strategy

[mrubens]

Also noticed this was the wrong string key