Bump stil4m/elm-syntax from 7.2.9 to 7.3.1 in /review

Bumps [stil4m/elm-syntax](https://github.com/stil4m/elm-syntax) from 7.2.9 to 7.3.1.
- [Changelog](https://github.com/stil4m/elm-syntax/blob/master/CHANGELOG.md)
- [Commits](stil4m/elm-syntax@7.2.9...7.3.1)

---
updated-dependencies:
- dependency-name: stil4m/elm-syntax
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

review/elm.json

@@ -16,7 +16,7 @@
             "jfmengels/elm-review-documentation": "2.0.3",
             "jfmengels/elm-review-simplify": "2.0.32",
             "jfmengels/elm-review-unused": "1.2.0",
-            "stil4m/elm-syntax": "7.2.9"
+            "stil4m/elm-syntax": "7.3.1"
         },
         "indirect": {
             "elm/html": "1.0.0",