Clang-format includes for piped_process

So that the changes in the following commit do not get mixed in with
clang-format related include re-ordering.

Author: thomasspriggs

src/util/piped_process.cpp

@@ -88,16 +88,16 @@
 #  include <unistd.h> // library for read/write/sleep/etc. functions
 #endif
 
-#  include <cstring> // library for strerror function (on linux)
-#  include <iostream>
-#  include <vector>
+#include "exception_utils.h"
+#include "invariant.h"
+#include "narrow.h"
+#include "optional.h"
+#include "piped_process.h"
+#include "string_utils.h"
 
-#  include "exception_utils.h"
-#  include "invariant.h"
-#  include "narrow.h"
-#  include "optional.h"
-#  include "piped_process.h"
-#  include "string_utils.h"
+#include <cstring> // library for strerror function (on linux)
+#include <iostream>
+#include <vector>
 
 #ifdef _WIN32
 #  define BUFSIZE (1024 * 64)

src/util/piped_process.h

@@ -15,6 +15,7 @@ typedef void *HANDLE;                                    // NOLINT
 
 #include "nodiscard.h"
 #include "optional.h"
+
 #include <vector>
 
 #define PIPED_PROCESS_INFINITE_TIMEOUT                                         \