Utilities: Replace ctype.h usage with AK/CharacterTypes.h

Author: https://github.com/AtkinsSJ
Commit: 0f95ff64ed
Pull-request: https://github.com/SerenityOS/serenity/pull/17793
Reviewed-by: https://github.com/krkk
Reviewed-by: https://github.com/trflynn89

Userland/Utilities/killall.cpp

@@ -5,6 +5,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/CharacterTypes.h>
 #include <AK/DeprecatedString.h>
 #include <LibCore/ProcessStatisticsReader.h>
 #include <LibCore/System.h>
@@ -48,7 +49,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
         Optional<unsigned> number;
 
-        if (isalpha(arguments.argv[1][1])) {
+        if (is_ascii_alpha(arguments.argv[1][1])) {
             int value = getsignalbyname(&arguments.argv[1][1]);
             if (value >= 0 && value < NSIG)
                 number = value;