style(3p/nix): Reformat project in Google C++ style

Reformatted with:

    fd . -e hh -e cc | xargs clang-format -i

third_party/nix/src/libstore/serve-protocol.hh

@@ -6,19 +6,19 @@ namespace nix {
 #define SERVE_MAGIC_2 0x5452eecb
 
 #define SERVE_PROTOCOL_VERSION 0x205
-#define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
-#define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
+#define GET_PROTOCOL_MAJOR(x) ((x)&0xff00)
+#define GET_PROTOCOL_MINOR(x) ((x)&0x00ff)
 
 typedef enum {
-    cmdQueryValidPaths = 1,
-    cmdQueryPathInfos = 2,
-    cmdDumpStorePath = 3,
-    cmdImportPaths = 4,
-    cmdExportPaths = 5,
-    cmdBuildPaths = 6,
-    cmdQueryClosure = 7,
-    cmdBuildDerivation = 8,
-    cmdAddToStoreNar = 9,
+  cmdQueryValidPaths = 1,
+  cmdQueryPathInfos = 2,
+  cmdDumpStorePath = 3,
+  cmdImportPaths = 4,
+  cmdExportPaths = 5,
+  cmdBuildPaths = 6,
+  cmdQueryClosure = 7,
+  cmdBuildDerivation = 8,
+  cmdAddToStoreNar = 9,
 } ServeCommand;
 
-}
+}  // namespace nix