fix: typo in `Object.hash` equality operator docs
fix: typo in `Object.hash` equality operator docs

Fix doc comments regarding equality operators in the newly added `Object.hash` and `Object.hashAll` methods.

Closes https://github.com/dart-lang/sdk/pull/47167
https://github.com/dart-lang/sdk/pull/47167

GitOrigin-RevId: 4e168df4b4e4ad932e12d8a90f73d724d830a9e3
Change-Id: I4b3902cbece98ee31d977882196f0c8ffc210694
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/212868
Reviewed-by: Kevin Moore <1d6e7d10d051cf619c5282da3c28fd8d3e0a65a4@google.com>
Commit-Queue: Kevin Moore <1d6e7d10d051cf619c5282da3c28fd8d3e0a65a4@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk