Merge pull request #21581 from zigmd/fix-typo-in-segset_t

std: fix typo in darwin segset_t

lib/std/c/darwin.zig

@@ -10,7 +10,7 @@ const mode_t = std.c.mode_t;
 const off_t = std.c.off_t;
 const pid_t = std.c.pid_t;
 const pthread_attr_t = std.c.pthread_attr_t;
-const sigset_t = std.c.segset_t;
+const sigset_t = std.c.sigset_t;
 const timespec = std.c.timespec;
 const sf_hdtr = std.c.sf_hdtr;