tree-wide: Sort includes

This was done by running a locally built clang-format with
https://github.com/llvm/llvm-project/pull/137617 and
https://github.com/llvm/llvm-project/pull/137840 applied on all .c
and .h files.

src/core/path.c

@@ -25,8 +25,8 @@
 #include "stat-util.h"
 #include "string-table.h"
 #include "string-util.h"
-#include "unit-name.h"
 #include "unit.h"
+#include "unit-name.h"
 
 static const UnitActiveState state_translation_table[_PATH_STATE_MAX] = {
         [PATH_DEAD]    = UNIT_INACTIVE,