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/search.cc b/third_party/nix/src/nix/search.cc
index b7cb586b0f..f44269eee5 100644
--- a/third_party/nix/src/nix/search.cc
+++ b/third_party/nix/src/nix/search.cc
@@ -244,7 +244,9 @@ struct CmdSearch : SourceExprCommand, MixJSON {
         /* Fun fact: catching std::ios::failure does not work
            due to C++11 ABI shenanigans.
            https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145 */
-        if (!jsonCacheFile) throw Error("error writing to %s", tmpFile);
+        if (!jsonCacheFile) {
+          throw Error("error writing to %s", tmpFile);
+        }
         throw;
       }