Expand the description of Wiglaf.

An one-dwarf raid to avenge his expelled folks seems to be a fitting task
for a champion of Okawaru.

I left the first sentence intact, as some IRCers defend it religiously.
This causes a stark contrast with my wordy extension -- can someone better
with writing reword it somehow?

crawl-ref/source/dat/descript/monsters.txt

@@ -339,7 +339,7 @@ end
 %%%%
 Wiglaf
 
-A fat dwarf wearing a stupid-looking hat.
+A fat dwarf wearing a stupid-looking hat. He's here to prove his worth to Okawaru by avenging his kin, the Mountain Dwarves, who were driven away from their lands by orcs and others, some of whom look just like you.
 {{
 if you.can_smell() then
     return "\nHe reeks of alcohol."