Document a coord in setup

Found it while attempting to decompile cmd 001a

src/include/setup/setup_000000.h

@@ -1,6 +1,7 @@
 #ifndef IN_SETUP_000000_H
 #define IN_SETUP_000000_H
 #include <ultra64.h>
+#include "types.h"
 
 extern u32 levelnum;
 extern u64 rand_seed;
@@ -15,4 +16,6 @@ extern u32 var0000c3f8;
 extern u32 var0000db50;
 extern u32 var0000db98;
 
+extern struct coord var0000f00c;
+
 #endif