style(3p/nix): Add braces around single-line for-loops r/772

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

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

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

1 files changed, 3 insertions, 1 deletions

diff --git a/third_party/nix/src/libstore/nar-info.cc b/third_party/nix/src/libstore/nar-info.cc
index cbc922a7daca..fa7d72c8ae30 100644
--- a/third_party/nix/src/libstore/nar-info.cc
+++ b/third_party/nix/src/libstore/nar-info.cc
@@ -122,7 +122,9 @@ std::string NarInfo::to_string() const {
     res += "System: " + system + "\n";
   }
 
-  for (auto sig : sigs) res += "Sig: " + sig + "\n";
+  for (auto sig : sigs) {
+    res += "Sig: " + sig + "\n";
+  }
 
   if (!ca.empty()) {
     res += "CA: " + ca + "\n";