style(3p/nix): Add braces around single-line conditionals r/771

These were not caught by the previous clang-tidy invocation, but were
instead sorted out using amber[0] as such:

    ambr --regex 'if (\(.+\))\s([a-z].*;)' 'if $1 { $2 }'

[0]: https://github.com/dalance/amber

1 files changed, 3 insertions, 1 deletions

diff --git a/third_party/nix/src/nix/hash.cc b/third_party/nix/src/nix/hash.cc
index e3278ea77a59..77be77cfcdc0 100644
--- a/third_party/nix/src/nix/hash.cc
+++ b/third_party/nix/src/nix/hash.cc
@@ -36,7 +36,9 @@ struct CmdHash : Command {
   void run() override {
     for (auto path : paths) {
       Hash h = mode == mFile ? hashFile(ht, path) : hashPath(ht, path).first;
-      if (truncate && h.hashSize > 20) h = compressHash(h, 20);
+      if (truncate && h.hashSize > 20) {
+        h = compressHash(h, 20);
+      }
       std::cout << format("%1%\n") % h.to_string(base, base == SRI);
     }
   }