Properly mark failed CI as failing

There was a syntax error in `if` condition for the `Result` CI job.
This meant that when a dependent job failed, the CI pipeline did not.
This should fix branch protection for the merge queue.

.github/workflows/rust.yml

@@ -133,12 +133,12 @@ jobs:
   build_result:
     name: Result
     runs-on: ubuntu-latest
-    # Integrity check is broken for the time being; don't require it.
     needs: ["mac", "linux", "windows"]
+    if: ${{ always() && github.event_name == 'push' }}
     steps:
       - name: Mark the job as successful
         run: exit 0
-        if: success()
+        if: ${{ success() }}
       - name: Mark the job as unsuccessful
         run: exit 1
-        if: "!success()"
+        if: ${{ !success() }}