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/libstore/machines.cc b/third_party/nix/src/libstore/machines.cc
index 99a32f653b8d..480d533e6099 100644
--- a/third_party/nix/src/libstore/machines.cc
+++ b/third_party/nix/src/libstore/machines.cc
@@ -50,7 +50,9 @@ void parseMachines(const std::string& s, Machines& machines) {
   for (auto line : tokenizeString<std::vector<string>>(s, "\n;")) {
     trim(line);
     line.erase(std::find(line.begin(), line.end(), '#'), line.end());
-    if (line.empty()) continue;
+    if (line.empty()) {
+      continue;
+    }
 
     if (line[0] == '@') {
       auto file = trim(std::string(line, 1));