tree-wide: drop string.h when string-util.h or friends are included

src/journal/catalog.c

@@ -4,7 +4,6 @@
 #include <fcntl.h>
 #include <locale.h>
 #include <stdio.h>
-#include <string.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>

src/journal/compress.c

@@ -2,7 +2,6 @@
 
 #include <inttypes.h>
 #include <stdlib.h>
-#include <string.h>
 #include <sys/mman.h>
 #include <sys/types.h>
 #include <sys/stat.h>

src/journal/journalctl.c

@@ -11,7 +11,6 @@
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <sys/inotify.h>
 #include <sys/stat.h>
 #include <unistd.h>

src/journal/journald-rate-limit.c

@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <errno.h>
-#include <string.h>
 
 #include "alloc-util.h"
 #include "hashmap.h"