bullwhip and polearm attack feedback

When testing the urgent message for having weapon be snagged by a
bullwhip, in between the occasional weapon grabs (which mention
flicking the bullwhip) I saw lots of regular attacks that said
"<mon> swings his bullwhip."  That is accurate but seems odd, so
change it to "<mon> lashes his bullwhip."  Do same for the hero.

While working on that, I discovered that monsters using a polearm
for a ranged attack always showed "<mon> thrusts <a polearm>" even
for ones that aren't defined as piercing so should be swung rather
that thrust.  And they're allowed to do that when adjacent where
there isn't enough room to thrust or swing a long polearm.  Now it's
"<mon> bashes with <a polearm>" in that situation.

src/mhitm.c

@@ -1116,11 +1116,16 @@ rustm(struct monst *mdef, struct obj *obj)
 }
 
 static void
-mswingsm(struct monst *magr, struct monst *mdef, struct obj *otemp)
+mswingsm(
+    struct monst *magr, /* attacker */
+    struct monst *mdef, /* defender */
+    struct obj *otemp)  /* attacker's weapon */
 {
     if (flags.verbose && !Blind && mon_visible(magr)) {
-        pline("%s %s %s%s %s at %s.", Monnam(magr),
-              (objects[otemp->otyp].oc_dir & PIERCE) ? "thrusts" : "swings",
+        boolean bash = (is_pole(otemp)
+                        && dist2(magr->mx, magr->my, mdef->mx, mdef->my) <= 2);
+
+        pline("%s %s %s%s %s at %s.", Monnam(magr), mswings_verb(otemp, bash),
               (otemp->quan > 1L) ? "one of " : "", mhis(magr), xname(otemp),
               mon_nam(mdef));
     }