strange object vs generic objects

Try to fix a fuzzer issue.  I wasn't able to reproduce it so am not
sure whether this actually fixes it.  A mimic seemed to be mimicking
object #1 (generic ILLOBJ_CLASS object which shouldn't occur) rather
than #0 (strange object).  Strange object always has dknown==1 and
generic objects should always have dknown==0 but farlook of mystery
object #1 had its dknown flag set.

An earlier fix to force non-Null oc_name when formatting objects in
order to pacify the static analyzer might have been the reason that
the problem couldn't be reproduced.

This includes a few miscellaneous changes made while unsuccessfully
hunting for the problem.

src/pager.c

@@ -296,8 +296,10 @@ object_from_map(int glyph, coordxy x, coordxy y, struct obj **obj_p)
 }
 
 static void
-look_at_object(char *buf, /* output buffer */
-               coordxy x, coordxy y, int glyph)
+look_at_object(
+    char *buf, /* output buffer */
+    coordxy x, coordxy y,
+    int glyph)
 {
     struct obj *otmp = 0;
     boolean fakeobj = object_from_map(glyph, x, y, &otmp);