Refactor to use `SharedString` in more places (#23813)

Splitting this off from
https://github.com/zed-industries/zed/pull/23808, per @maxdeviant's
suggestion!

Release Notes:

- N/A

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Co-authored-by: Nathan <nathan@zed.dev>
33d1145c3fRichard Feldman committed on 1/29/2025, 12:04:21 AM· committed by GitHubparent92a1cb8
15 files changedLine totals unavailable