more not PR #1102 - reveal_terrain() args

From a comment w/ diff in the pull request by entrez, combine the
show-full-map flag (available in wizard mode and explore mode) with
the bitmask for map-only, map-and-traps, map-and-traps-and-objects
flags for #terrain mode (and getpos() help) instead of passing that
as a separate argument.  No change in behavior unless I messed up.

include/extern.h

@@ -369,7 +369,7 @@ extern void sokoban_detect(void);
 #ifdef DUMPLOG
 extern void dump_map(void);
 #endif
-extern void reveal_terrain(int, int);
+extern void reveal_terrain(unsigned);
 extern int wiz_mgender(void);
 
 /* ### dig.c ### */