Restore the commit between assertion blocks

```git-check-assertions
run ./test/git-check-assertions.bats
assert_success

git checkout HEAD~ bin
run ./test/git-check-assertions.bats
assert_failure
assert_output --partial "not ok 10 should restore the commit between assertion blocks in one commit message"
```

bin/git-check-assertions

@@ -121,6 +121,7 @@ for commit_hash in "${commits[@]}"; do
       exit 1
     fi
     restore
+    git -c advice.detachedHead=false checkout -q "$commit_hash"
   done
   printf '%s\n' "$commit_hash" >>.git-check-assertions-cache
   echo