prompt-util: trivial header cleanups (#40407)

src/shared/prompt-util.c

@@ -2,7 +2,7 @@
 
 #include <unistd.h>
 
-#include <sd-varlink.h>
+#include "sd-varlink.h"
 
 #include "alloc-util.h"
 #include "glyph-util.h"

src/shared/prompt-util.h

@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
 #include "shared-forward.h"
 
 typedef enum PromptFlags {