Everywhere: Switch from (void) to [[maybe_unused]] (#4473)

Problem:
- `(void)` simply casts the expression to void. This is understood to
  indicate that it is ignored, but this is really a compiler trick to
  get the compiler to not generate a warning.

Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.

Note:
- Functions taking a `(void)` argument list have also been changed to
  `()` because this is not needed and shows up in the same grep
  command.

1 files changed, 2 insertions, 5 deletions

diff --git a/Userland/more.cpp b/Userland/more.cpp
index 4ff672000b..94b34e44cb 100644
--- a/Userland/more.cpp
+++ b/Userland/more.cpp
@@ -36,15 +36,12 @@ static void wait_for_key()
     printf("\033[7m--[ more ]--\033[0m");
     fflush(stdout);
     char dummy;
-    (void)read(key_fd, &dummy, 1);
+    [[maybe_unused]] auto rc = read(key_fd, &dummy, 1);
     printf("\n");
 }
 
-int main(int argc, char** argv)
+int main([[maybe_unused]] int argc, [[maybe_unused]] char** argv)
 {
-    (void)argc;
-    (void)argv;
-
     if (pledge("stdio rpath tty", nullptr) < 0) {
         perror("pledge");
         return 1;