<Mon> suddenly appears! vs ^G

For ^G, throttle the monster creation feedback.  Don't say "suddenly"
and don't exclaim the message, just say "<Mon> appears."  Also, use
Norep() so creating lots of similar monsters at once only gives a few
messages (just one unless varied by "next to you" vs "nearby" vs no
qualifier for farther away).  And for mimics created as objects or
furniture, report the sudden appearance of new object or furniture.

src/pager.c

@@ -161,10 +161,10 @@ trap_description(char *outbuf, int tnum, int x, int y)
 /* describe a hidden monster; used for look_at during extended monster
    detection and for probing; also when looking at self */
 void
-mhidden_description(struct monst *mon,
-                    boolean altmon, /* for probing: if mimicking a monster,
-                                       say so */
-                    char *outbuf)
+mhidden_description(
+    struct monst *mon,
+    boolean altmon, /* for probing: if mimicking a monster, say so */
+    char *outbuf)
 {
     struct obj *otmp;
     boolean fakeobj, isyou = (mon == &g.youmonst);