granular verbose message suppression mechanics

Switch to using a macro invocation Verbos(n, s) in place of the
flags.verbose checks.

Provide the mechanics for individual suppression of any of the
existing messages that were considered verbose.

Mechanics only - this code update does not provide any means of
setting the suppression bits.

iflags.verbose = 0
is still a master suppression of all the verbose messages.

iflags.verbose = 1
turns on the verbose messages only for those whose suppression
bit is 0 (not set).

src/apply.c

@@ -414,7 +414,7 @@ use_stethoscope(struct obj *obj)
             pline("%s %s %s really %s.",
                   use_plural ? "Those" : "That", what,
                   use_plural ? "are" : "is", mnm);
-        } else if (flags.verbose && !canspotmon(mtmp)) {
+        } else if (Verbose(0, use_stethoscope) && !canspotmon(mtmp)) {
             There("is %s there.", mnm);
         }