ghostty.h: guard sys/types.h include for MSVC

sys/types.h is a POSIX header that does not exist on MSVC. Move it
into the #else branch of the existing _MSC_VER guard that already
provides ssize_t via BaseTsd.h.

include/ghostty.h

@@ -15,11 +15,12 @@ extern "C" {
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
-#include <sys/types.h>
 
 #ifdef _MSC_VER
 #include <BaseTsd.h>
 typedef SSIZE_T ssize_t;
+#else
+#include <sys/types.h>
 #endif
 
 //-------------------------------------------------------------------