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/systemctl/systemctl-kill.c

@@ -3,9 +3,9 @@
 #include "bus-error.h"
 #include "bus-locator.h"
 #include "bus-wait-for-units.h"
+#include "systemctl.h"
 #include "systemctl-kill.h"
 #include "systemctl-util.h"
-#include "systemctl.h"
 
 int verb_kill(int argc, char *argv[], void *userdata) {
         _cleanup_(bus_wait_for_units_freep) BusWaitForUnits *w = NULL;